2015 Snohomish County Hazard Mitigation Plan Update

Transcription

1 2015 Snhmish Cunty Hazard Mitigatin Plan Update Public Wrkshp Hazards and Risks Infrmatin Overall Cunty Hazards Ranking Overall Cunty Impacts Ranking 1. Earthquake 2. Severe Weather 3. Flding 4. Landslide & Mass Mvements 5. Climate Change 6. Dam Failure 7. Tsunami/Seiche 8. Wildland Fire 9. Avalanche & Vlcan 10. Hazardus Materials Tier II/ Pipelines 11. Levy Failure 1. Resilience f infrastructure 2. Reliability f lcal emergency peratins 3. Vulnerability f structures 4. Insufficient warning f damaging events 5. Disruptin f lcal gvernment peratins 6. Cst-effectiveness f mitigatin prjects 7. Islatin & Insufficient incentives fr hazards mitigatin 8. Insufficient actinable risk reductin infrmatin available t public 9. Threats psed by cmpeting fldplain management and agricultural bjectives 10. Threatened natural values (ecsystem gds and services) 11. Reduced available pen space 12. Reduce the adverse impact f disasters n islated cmmunities. 13. Reduce the adverse impacts, and explit beneficial functins, f natural hazards t resurce lands. 1 P age

2 Snhmish Cunty Hazards Overview Hazards were based n the 2010 Snhmish Cunty Natural Hazard Mitigatin Plan and then updated by the 2015 Hazard Mitigatin Plan Planning Cmmittee. Additinal hazards addressed in the 2015 plan include hazardus materials/pipelines and levee failure. Avalanche Avalanches ccur when stress n a snwpack exceeds the strength f the snwpack. Mst avalanches are naturally triggered, where the weather (wind, snw, rain r sun) stress the snwpack t its breaking pint. Althugh mst avalanches are naturally triggered, in 92 percent f avalanche accidents the avalanche is triggered by the victim r smene in the victim s party. Avalanches can ccur whenever a sufficient depth f snw is depsited n slpes steeper than abut 20 degrees, with the mst dangerus cming frm slpes in the 35- t 40-degree range. Althugh terrain features, weather cnditins and snw pack prfiles can indicate areas f higher risk, avalanches can ccur with little r n warning. Avalanches regularly clse SR-2 abve Index, as well as many f the smaller access rads at higher elevatins. The rise in winter recreatin has increased the number f peple expsed t avalanches. Critical facilities in the cunty expsed t avalanches include SR 2 and the BNSF railrad. The Nrthwest Avalanche Center (NWAC) is a reginal surce f infrmatin n avalanche danger that can be accessed via the internet. Dam/Levee Failure Dam and levee failures are uncntrlled releases f water due t structural deficiencies. High risk dams in the Snhmish Cunty, which with failure wuld likely cause fatalities, include: Cedar Way Strmwater Detentin Dam n Lyns Creek Chaplin lake Nrth Dam n Wds Creek Chaplin Lake Suth Dam n Chaplin Creek Culmback Dam n the Sultan River Everett Reservir #3 n Pigin Creek 2 P age

3 Tlt River Dam n the Suth Frk f the Tlt River At this time, dam wner Emergency Actin Plans that include dam failure inundatin mapping are nt available fr every dam in the Cunty. Inundatin data are available fr the Culmback Dam and Tlt Dam. Warning time fr dam r levee failure can vary depending n the cause f failure. Large flds due t precipitatin and snw melt can ften be anticipated, giving time fr evacuatin if structure failure is anticipated. Als, dams and levees tend nt t fail cmpletely r instantaneusly. Mre flding, which is anticipated with climate change, increases the risk f spillway releases frm dams and structural failure f levees. Earthquake Earthquakes are a shaking f the grund caused by an abrupt shift f rck alng a fracture in the earth r a cntact zne between tectnic plates. Earthquakes are typically measured in bth magnitude and intensity. There are three types f earthquakes in the regin: Cascade Subductin Zne inter-plate mvement Beniff deep intra-plate mvement Shallw Crustal zne mvement Earthquakes are cmmn in the regin. Between January 2010 and August 2014 the Puget Sund regin experienced 21 earthquakes f a 3.0 magnitude r greater. With the strngest having a 3.9 magnitude. Snhmish Cunty is in an active seismic zne, with Suth Whidbey Island fault, the Devil s Muntain fault and pssibly the Everett fault presenting the greatest risks t cunty residents. The USGS estimated that a Cascadia Subductin Zne earthquake has a 10 t 15 percent prbability f ccurrence in 50 years, and has a recurrence interval f abut 500 t 600 years. In general, it is difficult t estimate the prbability f ccurrence f crustal earthquake events. Earthquakes n the Suth Whidbey Island and Seattle Faults have a 2 percent prbability f ccurrence in 50 years. A Beniff zne earthquake has an 85 percent prbability f ccurrence in 50 years, making it the mst likely f the three types. There is n reliable way t predict a day r mre in advance that an earthquake will ccur. Hwever, new warning systems may be able t prvide apprximately 40 secnds ntice prir t a large earthquake. Intensity experienced depends n strength f earthquake, gelgical substrate, and distance frm surce. Vulnerability is greater fr unreinfrced masnry and cncrete structures, and buildings built befre Snhmish Cunty is running scenaris t estimate the ptential impacts frm a Suth Whidbey Island Fault and a Devil s Muntain Fault. Earthquakes in the regin utside f the cunty culd als impact Snhmish Cunty as reginal transprtatin, electrical and cmmunicatins netwrks culd be disrupted. 3 P age

4 Fld A fld is the inundatin f nrmally dry land resulting frm the rising and verflwing f a bdy f water. A fldplain is the land area alng the sides f a river that becmes inundated with water during a fld. A 100-year fldplain is the area flded that has a 1-percent chance f being equaled r exceeded each year. This is a statistical average nly; in fact, a 100-year fld can ccur mre than nce in a shrt perid f time. The 1-percent annual chance fld is the standard used by mst federal and state agencies. Flding is the natural hazard f mst cncern in Washingtn and affects lives in the state every winter and spring. Fld mnitring, frecasting, and warning methds allw fr planning f respnses t ptential flds, but fld-inundatin maps needed by lcal planning agencies t assess flding and fldplain issues are seriusly utdated. Fld frequency and magnitude are the basis fr many planning decisins, but limited databases and changing cnditins make determinatin f 100-year flds and ther frequency discharges an uncertain science. Human activities tend t cncentrate in fldplains fr a number f reasns: water is readily available; land is fertile and suitable fr farming; transprtatin by water is easily accessible; and land is flatter and easier t develp. But human activity in fldplains frequently interferes with the natural functin f fldplains. It can affect the distributin and timing f drainage, thereby increasing fld prblems. Human develpment can create lcal flding prblems by altering r cnfining drainage channels. This increases fld ptential in tw ways: it reduces the stream s capacity t cntain flws, and it increases flw rates r velcities dwnstream during all stages f a fld event. The Natinal Fld Insurance Prgram (NFIP) makes federally backed fld insurance available t hmewners, renters, and business wners in cmmunities participating in the prgram. Currently, 20 jurisdictins in Snhmish Cunty participate in the NFIP. Participants in the NFIP must, at a minimum, regulate develpment in fldplain areas in accrdance with NFIP criteria. Befre issuing a permit t build in a fldplain, participating jurisdictins must ensure that three criteria are met: New buildings and develpments underging substantial imprvements must, at a minimum, be elevated t prtect against damage by the 100-year fld. New fldplain develpments must nt aggravate existing fld prblems r increase damage t ther prperties. New fldplain develpment must exercise a reasnable and prudent effrt t reduce its adverse impacts n threatened salmnid species, per the bilgical pinin issued by the Natinal Marine Fisheries Service. Snhmish Cunty and all participating cities in the planning area are currently in cmpliance and gd standing with the prvisins f the NFIP. The current effective date fr the cuntywide FIRM is September 16, Preliminary Digital Fld Insurance Maps (DFIRMs) were released in 2010, hwever their adptin has been put n hld pending FEMA s reslutin f the levee and analysis and mapping apprach. The DFIRMs, when adpted, are expected t mre accurately depict special fld hazard areas and fldways. The Cmmunity Rating System (CRS) is a vluntary incentive prgram that ffers discunted fld insurance premiums t encurage fldplain management activities beynd the minimum NFIP 4 P age

5 requirements. CRS class ratings are assigned t participating cmmunities based n 18 activities in the fllwing categries: Public infrmatin Mapping and regulatins Fld damage reductin Fld preparedness In Snhmish Cunty, the Cities f Mnre and Sultan, and the Twn f Index are currently participating in the CRS prgram. Winter flds ccur in mst f the Cunty s fldplains every 2 t 5 years. Majr flds n rivers and streams within Snhmish Cunty are caused by rainstrms between Octber and March. Thugh fldwaters are primarily frm rainfall, they are ften augmented by snwmelt. The ptential fr flding in lw-lying castal areas exists when favrable atmspheric cnditins (i.e., very lw pressure) ccur simultaneusly with perids f unusually high tides. N significant damage has been experienced in Snhmish Cunty in the recent past due t tidal flding. Strm surges, als knwn as strm tides, can affect a number f beachfrnt areas in the Cunty. Generally, strm surges are caused by an increase in the usual tide level by a cmbinatin f lw atmspheric pressure and nshre winds. During a strm surge, tides may run 2 t 4 feet abve the predicted tide level. Strm surges can usually be predicted up t 12 hurs befre ccurrence; hwever, nly an apprximate height can be predicted because f the large number f variables. The effects f a strm surge generally range frm saltwater inundatin t the battering f beachhead prperty by water driven debris. The beachfrnt areas in Snhmish Cunty mst likely t receive strm surge damage are near Mukilte, Marysville, the Tulalip Reservatin, Hat Island and Stanwd. The tw key factrs that cntribute t urban flding are rainfall intensity and duratin. Tpgraphy, sil cnditins, urbanizatin and grundcver als play an imprtant rle. Urban flding ccurs when available cnveyance systems lack the capacity t cnvey rainfall runff t nearby creeks, streams and rivers. As drainage facilities are verwhelmed, rads and transprtatin crridrs becme cnveyance facilities. Accrding t University f Washingtn scientists using mderate emissins scenaris, glbal climate changes resulting in warmer, wetter winters are prjected t increase flding frequency in mst Western Washingtn river basins. Future flds are expected t exceed the capacity and prtective abilities f existing fld prtectin facilities, threatening lives, prperty, majr transprtatin crridrs, cmmunities and reginal ecnmic centers. Landslides A landslide is the sliding mvement f masses f lsened rck and sil dwn a hillside r slpe. Slpe failures ccur when the strength f the sils frming the slpe is exceeded by the pressure, such as weight r saturatin, acting upn them. Mudslides r mudflws (r debris flws) are rivers f rck, earth, rganic matter and ther sil materials saturated with water. They develp in the sil verlying bedrck n slping surfaces when water rapidly accumulates in the grund, such as during heavy rainfall r rapid snwmelt. 5 P age

6 A sinkhle is a cllapse depressin in the grund with n visible utlet. Its drainage is subterranean, and it is cmmnly vertical-sided r funnel-shaped. All these mass mvements are caused by a cmbinatin f gelgical and climate cnditins. The cl, rainy Pacific Nrthwest climate ensures that sil misture levels remain high thrughut mst f the year, and in fact are ften at r near saturatin during wet winter mnths. The regin is als shaped by sils depsits frm glaciers, which are highly erdible. In additin, these vulnerable natural cnditins are being steadily affected by human residential, agricultural, cmmercial and industrial develpment and the infrastructure that supprts it. In general, landslide hazard areas are where the land has characteristics that cntribute t the risk f the dwnhill mvement f material, such as the fllwing: A slpe greater than 33 percent A histry f landslide activity r mvement during the last 10,000 years Stream r wave activity, which has caused ersin, undercut a bank r cut int a bank t cause the surrunding land t be unstable The presence r ptential fr snw avalanches The presence f an alluvial fan, indicating vulnerability t the flw f debris r sediments The presence f impermeable sils, such as silt r clay, which are mixed with granular sils such as sand and gravel. Current land-slide hazards maps d nt identify areas at risk f slide run-ut. The length f slide run-ut is affected by many factrs such as substrate cmpsitin, saturatin and slpe angle and height. Scientific research is nging t understand hw these and ther factrs determine slide run-ut. Landslides are ften triggered by ther natural hazards such as earthquakes, heavy rain, flds r wildland fires. In Snhmish Cunty, landslides typically ccur during and after majr strms. Mass mvements can ccur suddenly r slwly. The velcity f mvement may range frm a slw creep f inches per year t many feet per secnd, depending n slpe angle, material and water cntent. It is pssible t determine what areas are at risk during general time perids. Assessing the gelgy, vegetatin, and amunt f predicted precipitatin fr an area can help in these predictins. Hwever, there is n practical warning system fr individual landslides. Landslides destry prperty and infrastructure and can take the lives f peple. Slpe failures in the United States result in an average f 25 lives lst per year and an annual cst t sciety f abut $1.5 billin. The Hwy 530 landslide in 2014 resulted in 43 lives lst and is estimated t cst mre than $50 millin in damage and recvery csts. Prjected changes in winter weather, snwpack ability t hld water and impacts n vegetatin due t climate change wuld increase the prbability f landslides in the Cunty. Severe Weather West f the Cascade Muntains, summers are cl and relatively dry and winters are mild, wet and generally cludy. Measurable rainfall ccurs n 150 days each year in interir valleys and n 190 days in the muntains and alng the cast. 6 P age

7 Thunderstrms ccur up t 10 days each year ver the lwer elevatins and up t 15 days ver the muntains. Damaging hailstrms are rare in Western Washingtn. Snwfall is light in the lwer elevatins and heavy in the muntains. During the wet seasn, rainfall is usually f light t mderate intensity and cntinuus ver a lng perid rather than ccurring in heavy dwnpurs fr brief perids; heavier intensities ccur alng the windward slpes f the muntains. The strngest winds are generally frm the suth r suthwest and ccur during fall and winter. In interir valleys, wind velcities reach 40 t 50 mph each winter, and 75 t 90 mph a few times every 50 years. Funnel cluds r trnads ccasinally frm. The highest summer and lwest winter temperatures generally ccur during perids f easterly winds. Severe winter strms have a 58% prbability f ccurring in Snhmish Cunty within a tw year time perid. July and August are the driest mnths where tw t fur weeks can pass with nly a few r n rain shwers. The effects n Snhmish Cunty f a strng thunderstrm, trnad, windstrm r ice strm are likely t be similar: fallen trees, dwned pwer lines and interruptin f transprtatin lifelines, damaged hmes and public buildings. Immbility and lss f utilities are the mst cmmn impacts. Weather-related fatalities are uncmmn in western Washingtn, but they can ccur. Meterlgists can ften predict the likelihd f a severe strm. This can give several days f warning time. Hwever, meterlgists cannt predict the exact time f nset r severity f the strm. Sme strms may cme n mre quickly and have nly a few hurs f warning time. Climate change presents a significant challenge fr risk management assciated with extreme weather. The frequency f extreme weather events has increased steadily ver the last century. The number f weatherrelated disasters during the 1990s was fur times that f the 1950s, and cst 14 times as much in ecnmic lsses. Histrical data shws that the prbability fr severe weather events increases in a warmer climate. Tsunami/Seiche A tsunami is a series f traveling cean waves f extremely lng wavelength usually caused by displacement f the cean flr and typically generated by seismic r vlcanic activity r by underwater landslides. A seiche is a standing wave in an enclsed r partly enclsed bdy f water, nrmally caused by earthquake activity, and can affect harbrs, bays, lakes, rivers and canals. Tsunamis are typically classified as lcal r distant. Lcally generated tsunamis have minimal warning times. In the pen cean, a tsunami may be nly a few inches r feet high, but it can travel with speeds appraching 600 miles per hur. As a tsunami enters the shaling waters near a castline, its speed diminishes, its wavelength decreases, and its height increases greatly. 7 P age

8 N written recrds exist f damaging waves in Puget Sund. Hwever, verbal accunts amng the Snhmish Tribe reprted by Clin Tweddell in 1953 describe a great landslide-induced wave caused by the cllapse f Caman Head at the suth end f Caman Island arund the 1820s and 1830s. Area lakes have experienced seiches in histrical times. In 1891, an earthquake near Prt Angeles caused an 8-ft seiche in Lake Washingtn. Seiches generated by the 1949 Queen Charltte Islands earthquake were reprted n Lake Unin and Lake Washingtn. The Washingtn Department f Natural Resurces (DNR), wrking with the Natinal Oceanic and Atmspheric Administratin (NOAA) and the Natinal Tsunami Hazard Mitigatin Prgram, is in the prcess f mdeling tsunami impacts in Puget Sund using cmputer mdels f earthquake-generated tsunamis frm nearby seismic surces. The Cascadia subductin zne will prduce the state s largest tsunami, althugh it is nt likely t significantly impact Snhmish Cunty. Typical signs f a tsunami hazard are earthquakes and/r sudden and unexpected rise r fall in castal water. The large waves are ften preceded by castal flding and fllwed by a quick recessin f the water. Tsunamis are difficult t detect in the pen cean; with waves less than 3 feet high. The tsunami s size and speed, as well as the castal area s frm and depth, affect the impact f a tsunami; wave heights f 50 feet are nt uncmmn. In general, scientists believe it requires an earthquake f at least a magnitude 7 t prduce a tsunami. Seiches are usually earthquake-induced but typically d nt ccur clse t the epicenter f an earthquake, but hundreds f miles away. The Pacific tsunami warning system evlved frm a prgram initiated in It is a cperative effrt invlving 26 cuntries alng with numerus seismic statins, water level statins and infrmatin distributin centers. The warning system nly begins t functin when a Pacific basin earthquake f magnitude 6.5 r greater triggers an earthquake alarm. This system is nt cnsidered t be effective fr cmmunities lcated clse t the tsunami because the first wave wuld arrive befre the data were prcessed and analyzed. In this case, strng grund shaking wuld prvide the first warning f a ptential tsunami. Lw elevatin castal areas culd experience tsunami inundatin, and steep slpes adjacent t the cast culd experience ersin frm a tsunami. Sea level rise frm climate change culd increase tsunami inundatin and ersin impacts. Vlcan/Lahar The hazards related t vlcanes and vlcanic eruptins are distinguished by the different ways in which vlcanic materials and ther debris flw frm the vlcan. The lava may flw ut as a viscus liquid, r it may explde frm the vent as slid r liquid particles. A lahar is a rapidly flwing mixture f water and rck debris that riginates frm a vlcan. 8 P age

9 Glacier Peak in eastern Snhmish Cunty is ne f the majr Cascade vlcanes. The muntain is thught t have erupted as recently as the 18th century. Since the end f the last glacial episde abut 14,000 years ag, Glacier Peak has erupted at least a dzen times. Althugh a majr vlcanic debris flw is a rare ccurrence, its ptential vlume and destructive frce are such that the pssibility deserves mentin. The Twn f Darringtn and much f nrtheast Snhmish Cunty culd be affected by a large flw fllwing the White Chuck and Sauk River drainage channels. Mst f the Cunty wuld be expsed t ash fall and accumulatin in the event f a vlcanic eruptin. Three majr Cascade vlcanes ther than Glacier Peak are relatively clse t Snhmish Cunty: Munt Rainier is 60 miles t the suth; Munt St. Helens is 110 miles t the suth; and Munt Baker is 35 miles t the nrth. Munt Adams, als 110 miles t the suth but n the east side f the Cascade Range, pses a lwer threat because f the directin f prevailing winds. The explsive disintegratin f Munt St. Helens nrth flank in 1980 vividly demnstrated the pwer that Cascade vlcanes can unleash. A 1-inch deep layer f ash weighs an average f 10 punds per square ft, causing danger f structural cllapse. Ash is harsh, acidic and gritty, and it has a sulfuric dr. When an ash clud cmbines with rain, sulfur dixide in the clud cmbines with the rain water t frm diluted sulfuric acid that may cause minr, but painful burns t the skin, eyes, nse, and thrat. Cnstant mnitring f all active vlcanes means that there will likely be mre than adequate time fr evacuatin befre an event. Wildland Fire The wildland fire seasn in Washingtn usually begins in early July and ends with precipitatin in late September. Hwever, wildland fires have ccurred in every mnth f the year. Hw a fire behaves depends n fuels available, weather, thunderstrm activity, terrain, and time f day. Fires histrically burn n a fairly regular cycle, recycling carbn and nutrients stred in the ecsystem, and strngly affecting the species within the ecsystem. The burning cycle in western Washingtn is every 100 t 150 years. Cntrlled burns have als been cnducted because the fire cycle is an imprtant aspect f management fr many ecsystems. Accrding t data tracked by the DNR n lands that it is respnsible fr prtecting, Snhmish Cunty has had 905 wildland fire incidents since This is an average f a little ver 20 per year, with a high f 45 incidents in 1974 and 1990 and a lw f 1 incident in Ptential lsses frm wildland fire include human life, structures and ther imprvements, and natural resurces. There are n recrded incidents f lss f life frm wildland fires in Snhmish Cunty, and the risk frm wildland fire has been deemed mderate by the state. 9 P age

10 Wildland fires are typically caused by humans, whether intentinally r accidentally. There is n way t predict when ne might break ut. Reliable Natinal Weather Service lightning warnings are available n average 24 t 48 hurs prir t a significant electrical strm. Dry seasns and drughts are factrs that greatly increase fire likelihd. Once a fire has started, fire alerting is reasnably rapid in mst cases. Prjected warming, and increase in summer drught and frest diseases, assciated with climate change, wuld be expected t increase the risk f wildland fire in the cunty. Hazardus Materials/Pipelines Hazardus materials are materials with a chemical, physical, r bilgical nature which can pse a ptential risk t human health, prperty, r the envirnment when released. Hazardus materials incidents can ccur naturally and during the manufacture, transprtatin, strage and use f hazardus materials. These incidents can ccur as a result f human errr, natural hazards, deliberate deed, r a breakdwn in equipment r mnitring systems. These incidents can ccur as a result f human errr, natural hazards, deliberate deed, r a breakdwn in equipment r mnitring systems. The impact depends upn the quantity and physical prperties f the hazardus material, envirnmental and weather factrs at the pint f release, the type f release, and its prximity t human and wildlife ppulatins and valuable ecsystems. There are 668 reprted Tier II facilities lcated in Snhmish Cunty. Hwever, the majrity f these are smaller facilities, such as gas statins, that dn t pse a serius threat t a wide area. The main lcal rutes fr hazardus materials transprt are Interstate 5 (I-5) and I -405, State Rute (SR) 2 and 9 and Highway 99 and the BNSF railrad lcated thrughut the Cunty. Natural gas, cmmercial prpane and cmmercial butane, and liquefied petrleum gas (LPG) gas pipelines serve several strage farms in Snhmish Cunty, as well as all majr cities and twns. Olympic Pipeline Cmpany maintains tw majr liquid petrleum prduct pipelines thrugh Snhmish Cunty. Williams Natural Gas als perates a majr nrth-suth pipeline carrying vapr petrleum prducts. Many factrs determine the severity f a ptential incident including quick and slid decisin-making by emergency fficials, lcatin and type f release, evacuatin and shelter-in-place needs, public health cncerns, and relevant ecnmic cnsideratins. Additinally, while mst incidents are generally brief, the resulting recvery and cleanup may take time t exact. Hazardus materials releases can ccur at any time withut warning. Once the release has ccurred the ptentially affected areas may have little r n warning time, depending n which chemical was released and the methd by which the chemical will travel. The initial identificatin f specific hazardus materials types can increase respnse capabilities. 10 P age

11 Vulnerable ppulatins are all ppulatins that may be expsed t an incident and are incapable f escaping the area within the allwable time frame. Hazardus materials incidents can have a significant effect n the envirnment. Releases int the envirnment have the ptential t significantly damage sils, water quality, wildlife habitat, and vegetatin. Climate Change Cnsideratins fr Hazard Mitigatin Fr hazards that are affected by climate cnditins, the assumptin that future behavir will be equivalent t past behavir is nt valid if climate cnditins are changing. Climate change is expected t affect the fllwing hazards: Severe Weather Mst reginal climate mdels prject an increase f summer drught, with averages ranging frm 6 t 8 percent decrease in summer precipitatin by Winter, spring and fall precipitatin is prjected t increase ver the same perid. Fr high greenhuse gas scenari events, heavy rainfall events f 1 inch r greater are prjected t increase frm 6 t 20 % by 2050 than the average frm the late 1800 s thrugh Flding Peak streamflws are prjected t ccur 4 t 9 weeks earlier by the 2080s. Flding is prjected mre ften, with the streamflw vlume f the histric 100 year fld event ptentially ccurring as frequent as a 15 year event. Sea level rise will increase castal flding. Prjectins range frm a rise f 4 t 56 inches alng the Washingtn Cast. Landslides Sea level rise is expected t increase castal landslides. Prjected increases in winter, spring and fall precipitatin and increased frequency f heavy rain events is expected t increase the frequency f landslides n vulnerable slpes. Wildfire Increases in summer drught and insect infestatin f frests are expected t increase the risk f wildfires. Tsunami Higher sea levels wuld result in mre castal flding and ersin in the event f a tsunami. 11 P age

12 Avalanche The effects f climate change n avalanche frequency, magnitude and lcatin are uncertain. Prjected decreases in lw elevatin snw pack may result in fewer lw elevatin avalanches. Hwever, snwfall may increase in higher elevatin belw freezing znes, which culd increase avalanche hazard. Als, the type f avalanche culd change, ptentially increasing the number f wet snw avalanches. Dam/Levee Failure Increased winter, spring and fall precipitatin and severe strm events are nt expected t increase the risk f catastrphic dam failure. Hwever, design failure, where water is released ver the spillway wuld be expected t becme mre frequent. The risk f levee failure culd increase with an increased frequency f fld events. Hazardus Materials/Pipelines Hazardus materials sites in fld prne areas culd be a greater risk f a spill r release frm the prjected increases in frequency f fld events. 12 P age