2014 Washington and Oregon Fire Season Outlook

Size: px

Start display at page:

Download "2014 Washington and Oregon Fire Season Outlook"

Ashlie Parsons
5 years ago
Views:

1 2014 Washingn and Oregon Fire Season Outlook July 28, 2013 Large wildland fires in Southwest Oregon. Issued May 15, 2014 Paul Werth Fire Weather Meteorologist Weather Research and Consulting Services, LLC Battle Ground, WA

2 This page intentionally blank for convenience in printing

2014 Northwest Fire Season Outlook The following report is the 2014 fire season severity outlook for federal and state lands within Washingn and Oregon.

3 2014 Northwest Fire Season Outlook The following report is the 2014 fire season severity outlook for federal and state lands within Washingn and Oregon. The information in this document is based on a statistical model developed by Weather Research and Consulting Services, LLC that correlates hisric fire season acres burned, by agency, with the following predicrs: large scale Pacific Ocean sea surface temperature anomalies, upper level pressure patterns, seasonal precipitation, long-term drought, projected summer rainfall, and mountain snowpack information. With respect snowpack information, we developed a new index called the Spring Snowpack Index (SSPI) that combines Snow Water Equivalent (SWE) values and snowmelt rates, from National Resources Conservation Service (NRCS) SNOTEL stations, resulting in a number that integrates winter and spring weather (i.e. temperature, precipitation, and evaporation). Our test results for Washingn and Oregon ( ) indicate this index correlates much better with fire season severity than SWE alone. SSPI values can range from or higher. The lower the SSPI value, the higher the probability of an active fire season. The SSPI is the best predicr we use and contributed significantly the 2014 fire season outlook. More information concerning the SSPI, and projections for the Western States, can be found in this document and at: The forecast acres burned output from our model is used classify fire season severity, by fire agency, as,,, or Below. (The category, which represents the p 10% of acres burned based upon hisrical data, was added last year.) This information is then summarized and displayed in graphic and tabular formats. Winter and Spring Conditions Sea surface temperature (SST) anomalies in the Nino 3.4 region of the central Pacific Ocean (Fig. 1) were near slightly below normal for the second winter in a row, indicating a continuation of Neutral conditions (neither El Nino nor La Nina). Elsewhere across the Pacific, SST anomalies were very different from last year with warmer than normal water in the eastern Pacific and cooler than normal in the central and western Pacific. Although we are well in the cool phase of the Pacific Decadal Oscillation (PDO), this reversal of temperature pattern is more indicative of the warm phase. However, this pattern switch will likely be temporary. Figure 1. February 2014 Pacific Ocean Sea Surface Temperature Anomalies 1

The PDO alternates between warm and cool phases about every 30 years. The PDO was in a cool phase from 1945-1976 and a warm phase from 1977-2007.

The cool phase of the PDO typically produces colder, wetter winters and milder fire seasons in the Pacific Northwest.

4 The PDO alternates between warm and cool phases about every 30 years. The PDO was in a cool phase from and a warm phase from In Ocber 2007, the PDO abruptly reverted back a cool phase which will likely remain in place until The cool phase of the PDO typically produces colder, wetter winters and milder fire seasons in the Pacific Northwest. fire seasons in Oregon and Washingn are five times more likely occur during the warm phase of the PDO than the cool phase (based on USFS annual acres burned). However, winter precipitation patterns across the Western United States were again not typical of either a cool PDO or Neutral / La Nina ENSO phases. The upper level pressure pattern was more typical of El Nino early in the winter, but switched a more La Nina-like pattern after February 1. Washingn and Oregon were both mild and dry in December and January, resulting in very little mountain snow. But the weather turned Figure 2. Winter Percent of Normal Precipitation cold and wet in February and snowpack percentages significantly improved, especially in Washingn. Overall, winter and early spring were drier than normal for most of the Western United States (Fig. 2) except the northern Rocky Mountains. For most of the winter, the Polar Jet Stream remained farther north than usual, directing srms in western Canada then southward in the central and eastern portions of the United States. Many areas east of the Rocky Mountains experienced record cold and snow during the winter. Figure 3. April 1 Mountain Snowpack (SWE) 2 The Western United States winter snowpack (Fig. 3) mirrored the precipitation pattern: much below normal from southern Oregon and California (not shown on the map but reported by the California Department of Water Resources) central Utah southward in Arizona and New Mexico. normal snowpacks were reported from Washingn Montana and southward in Colorado. For the third year in a row, the snowpack was much better in Washingn than Oregon. The April 1 Washingn snowpack was 104% of normal, and Oregon s was only 59% of average. The snowpack in nearly every Washingn river basin was near above normal. However, the Oregon snowpack showed a steep decline from northeast southwest, ranging from 100% of normal in the Grande Ronde

River Basin only 31% in the Klamath River Basin. Near normal temperature and precipitation in April and early May produced only minor changes in SWE percentages.

In contrast, Washingn s May 15 snowpack of 114% was still above normal for mid-may.

5 River Basin only 31% in the Klamath River Basin. Near normal temperature and precipitation in April and early May produced only minor changes in SWE percentages. The May 15 Oregon snowpack was 54% of normal, a decline of only 6% from April 1. The Malheur and John Day River Basins were nearly snow free, the second time that has happened since In contrast, Washingn s May 15 snowpack of 114% was still above normal for mid-may. Based on May snowpack percentages, snowmelt dates are projected be 1-2 weeks earlier than usual in Oregon and about a week later than normal in Washingn. The earliest snowmelt dates occurred in the southern Oregon Cascades, as much as a month earlier than usual. This is the second year since 2007 that the snowmelt date will be earlier than usual in Oregon. Statistics show that active fire seasons often occur when snowmelt dates are early, resulting in lower fuel moisture and an extended period of large fire risk. Figure 4. WA and OR Mountain Snowpack (SWE) Trend Figure 4 displays the monthly snowpack trend in Washingn and Oregon this past winter. Of interest is: 1) the much below normal snowpack in early January, 2) the significant improvement in Washingn s snowpack during February, and 3) the overall much below normal Oregon snowpack. The winter precipitation deficit (Fig. 2) and the meager snowpack (Fig. 3) point continued drought conditions in much of Oregon. This is well depicted in the May 6 U.S. Drought Monir chart (Fig. 5) that shows severe extreme drought across southern Oregon. Figure 5. U.S. Drought Monir May 6,

Earlier in this report we stated that WRCS recently developed the Spring Snowpack Index (SSPI), which combines SWE values and snowmelt rates and has proven be an effective predicr of wildland fire

6 Earlier in this report we stated that WRCS recently developed the Spring Snowpack Index (SSPI), which combines SWE values and snowmelt rates and has proven be an effective predicr of wildland fire season severity in Washingn and Oregon. The SSPI has a range of or higher. The lower the SSPI number, the higher the probability of an active fire season. For example, values of 30 or less correlate well with severe fire seasons, while values less than 80 indicate above average fire seasons. The Oregon SSPI is unusually low at 62 and is similar the following years: 1991, 1994, 2001, 2002, 2004, 2005, 2007, 2012and Seven of these nine years experienced very active fire seasons. Meanwhile, the Washingn SSPI is 125, about the same as last year. The SSPI can be calculated for most river basins in the Western United States and Alaska by using NRCS SNOTEL and California Department of Water Resources data. Figure 6 displays this year s SSPI. It shows the lowest SSPI of -25 in Arizona and New Mexico and the highest in Montana with values above 175. Alaska, not shown on the map, has a statewide average SSPI of 49, down from last year s 195. Using SSPI correlations we have developed with fire season severity in Washingn and Oregon, a large portion of the Western United States has the potential for an above average severe 2014 fire season. This includes Arizona, New Mexico, Utah, California, Nevada and Oregon, southwestern Idaho and parts of southern Colorado. Figure Western United States Spring Snowpack Index (SSPI) 4

7 Projected Washingn and Oregon Summer Weather The 2014 summer weather scenario is based on winter Pacific Ocean sea surface temperature anomalies (Neutral ENSO and cool phase PDO ), a forecast of El Nino conditions developing this summer and fall (Fig. 7), and upper level pressure patterns (both this past winter and projected this summer). In the past sixty years there have been only five years with similar weather and sea surface temperature conditions: 1960, 1981, 1996, 2001 and Figure 7. Forecast Nino 3.4 SST Anomalies The location of the mean upper level ridge and trough during the summer is critical in determining the fire season severity in Washingn and Oregon. All five analog years listed above had similar upper level patterns, as displayed in Figure 8. With this pattern, the mean upper level ridge position is located near 105 degrees W (eastern Montana) and the upper trough near 130 degrees W (just off the Pacific Coast). Thus, the upper trough will likely be the primary influence on weather in western Washingn this summer. However, the upper ridge will be strong enough provide favorable conditions for periodic lightning events in Oregon and eastern Washingn. Figure 8. July/August Analog Upper Level Pattern Based on our research, the following are our projections for the 2014 Washingn and Oregon summer: Both July and August will be warmer and drier than normal. There will be three four lightning episodes. (A lightning episode is defined as 149 fires or more in a three-day period.) The best estimate is that the first episode will occur in early July. Lightning will be a mixture of wet and dry. There will be the usual number of marine pushes with strong winds east of the Cascades. East winds will cause fire problems in western Oregon in September. 5

Fire Season Outlook The Washingn and Oregon fire season outlook is based on algorithms that correlate past and future weather conditions fire occurrence data (acres burned, number of large fires).

8 Fire Season Outlook The Washingn and Oregon fire season outlook is based on algorithms that correlate past and future weather conditions fire occurrence data (acres burned, number of large fires). Significant facrs this year for Washingn and Oregon include: 1. Neutral ENSO conditions this winter with a moderate strong El Nino developing this summer, and 2. warmer than normal sea surface temperatures in the Gulf of Alaska and off the West Coast of the U.S. In Oregon, the following facrs also include: 1. a low SSPI value of 62, 2. snowmelt dates one two weeks earlier than usual, and 3. severe extreme drought conditions in the southern half of the state. These facrs will likely result in vastly different fire season conditions in Washingn and Oregon. Overall, Washingn will experience a near normal fire season with a typical start date. Oregon, on the other hand, will likely have an early and very active fire season, especially in southern and eastern Oregon. The best case scenario would be a much wetter than usual summer, but this has not occurred in any of the analog years. Based on these correlations, our outlook (map the right) is as follows: Washingn Most of the Washingn Cascades and northeast mountains will experience a Below fire season. The Columbia Basin and the lower eastern slopes of the Cascades have the potential for an season. An season is likely elsewhere in Washingn. Oregon Oregon s fire season will likely be. The only exceptions are the northwestern and northeastern corners of the state which most likely will experience an Below season. A high potential exists for large forest fires in central and southern Oregon. This includes the Ochoco, Malheur, Deschutes, Winema/Fremont, and Rogue/Siskiyou NFs, and the Oregon Department of Forestry. Problem forest fires are also possible on the Umpqua and Willamette NFs in western Oregon. Large grass fires are again a definite threat on the Prineville, Lakeview, Burns and Vale BLM. 6

9 The table below displays the following fire season severity information by agency: the number of acres projected be burned in 2014 (not including Wildland Fire Use fires), a listing of worst case acres burned, and the threshold for acres burned classify the severity of the fire season. Agency 2014 Fire Season Projected 2014 Acres Burned Worst Case Acres Burned Severity Breakpoints* (Acres Burned) USFS ,000 acres 280, ,000 A. Abv Avg 100,000 A. Avg 40,000 A. Blo Avg <40,000 A. BLM ,000 acres 280, ,000 A. Abv Avg 100,000 A. Avg 40,000 A. Blo Avg <40,000 A. BIA 30-50,000 acres 80,000 50,000 A. Abv Avg 25,000 A. Avg 10,000 A. Blo Avg <10,000 A. ODF 25-40,000 acres 60,000 40,000 A. Abv Avg 13,000 A. Avg 6,000 A. Blo Avg < 6,000 A. WADNR 15 25,000 acres 40,000 40,000 A. Abv Avg 12,000 A. Avg 5,000 A. Blo Avg < 5,000 A. * Severity breakpoint acres are based on the following years USFS BLM BIA ODF WADNR Severity breakpoints Below 90th percentile 67th percentile 34-66th percentile 33rd percentile 7

10 Summary and Fire Management Implications Oregon is likely have an fire season, especially in eastern and southern portions of the state. Eastern Washingn has the potential for an fire season, primarily in the Columbia Basin and the along east slopes of the Cascades. The remainder of the region is projected have an or Below fire season. Based on this projection, the summer fire season carries the following fire management implications: A high probability of large timber fires on all U.S. National Forest and Oregon Department of Forestry lands in eastern and southern Oregon An above average threat of large timber fires in western Oregon and the lower eastern slopes of the Washingn Cascades Large grass fires in the Columbia Basin and BLM lands in central and southeastern Oregon An early and longer than normal fire season in Oregon A high demand for all types of firefighting resources An above average number (65-80) of large fires (D - G) in Washingn and Oregon Planning Level IV and V days in the Northwest Geographic Area Beginning daily on June 2, information concerning the probability of large wildland fires for the next 14 day period will be available on our web site at 8

11 Verification of the 2013 Fire Season Outlook Weather Research and Consulting Services outlook for the 2013 Washingn and Oregon fire season verified very well. The outlook correctly predicted the above average severe fire season in Oregon, the above average fire season in eastern Washingn, and the below average fire season in western Washingn. The high potential for large forest fires projected for central and southern Oregon, including the Oregon Department of Forestry, did occur. The outlook s only miss was the projected USFS acres burned, which was significantly less than forecast. The table below compares the projected 2013 fire season by agency with the actual acres burned. Agency Projected 2013 Fire Season Actual 2013 Fire Season Projected 2013 Acres Burned Actual 2013 Acres Burned USFS Below ,000 acres Worst Case: 280,00 acres 37,936 acres BLM ,000 acres Worst Case: 280,00 acres 170,593 acres BIA 25 45,000 acres Worst Case: 60,00 acres 90,323 acres ODF 20-30,000 acres Worst Case: 58,00 acres 104,469 acres WADNR 12-24,000 acres Worst Case: 38,00 acres 93,656 acres * Severity breakpoint acres are based on the following years USFS BLM BIA ODF WADNR Severity breakpoints Below 90th percentile 67th percentile 34-66th percentile 33rd percentile 2013 acres burned data provided by the National Interagency Fire Center (NIFC), Northwest Interagency Coordination Center (NWCC), and Oregon Department of Forestry (ODF) 9

12 Below is a summary of the 2013 fire season by agency: The USFS burned 37,936 acres, far fewer than the ,000 acres projected by the WRCS model. This figure is about half of the 64,620 acres long-term average. The largest fire was the 17,891 acre Whiskey Complex (Umpqua NF) which started during the July 26 southwest Oregon lightning bust. Other large fires were the 2,352 acre Manastash Fire (Okanogan-Wenatchee NF) and the 2,923 acre Labrador Fire (Rogue- Siskiyou NF). The 170,593 BLM acres burned were within the range projected for the fire season, and nearly twice the long-term average of 93,706 acres. The largest fires all occurred on Vale BLM protected land: the 46,559 acre Owyhee Fire, the 26,000 acre Cedar Mountain Fire, and the 17,237 acre Grassy Mountain Fire. The 90,323 acres burned on BIA land was 30,000 acres more than the predicted worst case, but was well within the severe category threshold. It was the fourth largest number of acres burned since This tal compares the long-term average of 24,295 acres. Two large fires accounted for most of the burned acres: the Sunnyside Turnoff Fire (Warm Springs BIA) burned 51,340 acres; the Mile Marker 28 Fire (Yakima BIA) burned 26,092 acres. The Oregon Department of Forestry (ODF) reported 104,469 acres burned, the most since This figure compares the long-term average of 17,381 acres. Most of the acres burned were the result of the July 26 lightning bust in southwestern Oregon. Dry lightning ignited dozens of fires throughout southwestern Oregon, many of which merged and became large complexes. Two of the largest occurred on ODF protected land: the 48,679 acre Douglas County Complex and the 26,725 Big Windy Fire. Other large fires burned in central and eastern Oregon: the 12,161 acre CG Complex and the 11,354 acre Government Flats Complex. The Washingn Department of Natural Resources (WADNR) reported 93,656 acres burned, the most in 60 years dating back The vast majority of the acreage occurred on the Colockum Tarps Fire, which burned 80,184 acres near the Columbia River south of Wenatchee. The 2013 weekly acres burned (red) compared the average (blue) is displayed in Figure 8. Figure Weekly Washingn and Oregon Acres Burned Compared (Source: Incident Management Situation Report, National Interagency Coordination Center, Boise Idaho) 10

13 Although there were a few large BLM fires in June, the first significant activity of the fire season occurred the first week of July. This was about a week earlier than 2012 and nearly a month earlier than The last half of July was very active, especially after the southwest Oregon dry lightning bust on July 26. The following large southwest Oregon fires resulted from this lightning event: Whiskey Complex Douglas County Complex Labrador Fire Big Windy Fire Brimsne Fire Other large fires occurring during this time included: Central Oregon s Sunnyside Turnoff Fire started July 20 Central Washingn s Colockum Tarps Fire began on July 27 Another outbreak of large fires in eastern Oregon occurred the second week in August. The largest were: Cedar Fire Grassy Mountain Fire CG Complex After August 15, the number and size of large fires gradually decreased. Only minimal large fire activity occurred in September as the weather turned cool and very wet after September 17. In summary, the 2013 fire season started early and ended earlier than usual. The peak of the season, based upon the number of large fires and acreage burned, occurred between July 15 and August 15. The WRCS 2013 Fire Season Outlook predicted large fires (size classification D - G) Planning Level IV and V days The verified number was 67 large fires 29 tal days Both verified well as predicted by the WRCS Fire Season Severity Model. 11

Weather and Climate Summary and Forecast February 2018 Report

Weather and Climate Summary and Forecast February 2018 Report Gregory V. Jones Linfield College February 5, 2018 Summary: For the majority of the month of January the persistent ridge of high pressure