January 4, 2018 South Dakota Wildfire Potential Outlook - January 2018 - Happy New Year! The Legion Lake fire in and southeast of Custer State Park was the big headline of December 2017. Climate and weather factors pointed to the potential for large wildfire growth and it just so happened that an ignition occurred at the right place and right time (or wrong place and wrong time depending on perspective) for large fire growth. Luckily, the weather pattern drastically shifted for the rest of December with cold conditions and snow cover persisting through the end of 2017. Comparing to 2018 to past years We continue to see La Niña conditions across the Pacific Ocean and the last La Niña we saw was during the winter of 2011-2012. Remember that the summer of 2012 brought one of the worst fire seasons on record for much of the Rocky Mountain region. I draw the comparison only to make a point that these are the types of patterns that we observe to help us understand what the year might bring. I am by no means calling for a record wildfire year again in 2018 but we ll watch closely to see how the conditions evolve! Sincerely, Darren Clabo SD State Fire Meteorologist Firing operations on the Legion Lake wildfire. Photo credit: Darren Clabo Contents Page 1: Statewide current conditions and projected August conditions Page 2: Northwest SD Outlook Page 3: Northcentral SD Outlook Page 4: Northeast SD Outlook Page 5: Black Hills Outlook Page 6: Central SD Outlook Page 7: Eastcentral SD Outlook Page 8: Southwest SD Outlook Page 9: Southcentral SD Outlook Page 10: Southeast SD Outlook Page 11: Statewide Overview i
Current Climate/Soil Conditions January 2018 Forecast Conditions 1
for Northwestern SD - No significant correlations observed - NW Winds above 15 mph - Cold front passages - Much below average precipitation for 30 days - Minimum RH less than 30% - Above average temperatures 1.30.2007 Gilbert H 148 33/31 21% NW @ 32 D3-2.7 0.08 83 49.4 1.22.2002 Olson H 140 48/37 54% NW @ 24 D0-1.63 0.05 97-12.4 1.15.2012 Sprague U 40 40/31 29% NW @ 44 None 3.12 0.19 16 81.4 1.8.2008 Lockert H 25 40/30 28% WNW @ 14 D2-2.55 0.12 39 75 1.25.2014 Brickhouse H 6 61/37 25% NW @ 48 None 5.6 0.2 33 58 Northwestern SD Overview: Fires are uncommon during January in the Northwestern climate division. For fire activity to occur, dry conditions need to be observed for 30 days or more which leads to a lack of snow cover. Weather conditions for large fire growth include warm temperatures ahead of a cold front and the strong winds that occur before and after frontal passage. Northwestern SD January 2017 Outlook: - Colder than average temperatures and moderate snow cover are expected to persist. * Fire potential is relative to historical January fires across Northwestern SD. 2
for Northcentral SD - Above average temperature in January - Below average precipitation extending over one month - Well above average temperatures - Strong northwest winds in the post-cold front environment 1.6.2000 Grass 1030 H 25 32/25 41% NW @ 36 D0 4.16 0.03 82 105.6 1.16.2002 Grass U 10 28/26 60% NW @ 29 D0-0.56 0.03 100 147.7 1.2.2000 Grass 1029 H 8 42/25 58% NW @ 36 D0 4.16 0.03 81 119.8 1.3.2012 L&O Acres U 3 49/22 42% NNW @ 35 D0 3.28 0.29 6 171.9 1.21.2006 No Heart Housing H 2 45/30 36% NW @ 32 D1-0.22 0.76 21 132.7 Northcentral SD Overview: Since 2000, only fires of 25 acres or less have occurred in January making this month of one the least active fire months of the year. Strong northwest winds, very dry conditions, and above average temperatures are the common denominators for large fire growth. Northcentral SD January 2017 Outlook: - Below average temperatures are expected along with moderate snow cover. * Fire potential is relative to historical January fires across Northcentral SD. 3
Important Factors for Large Fire Growth in January for Northeastern SD - Prior Oct. Dec. precipitation deficits - Frontal passages - Exceptionally warm conditions 7-10 days prior to fire start - Much below average precipitation over the past 30 days 1.1.2000 Floyd Hoffman H 40 32/22 49% E @ 13 D0 2.3 0.15 99 183.5 1.9.2012 Lentsch U 20 53/23 35% W @ 35 D0 1.72 0.27 12 193 1.6.2012 Trust Land U 10 48/23 31% NW @ 38 D0 1.72 0.27 9 181.3 1.2.2012 Boehn U 5 57/22 34% W @ 12 D1 1.72 0.27 8 161.2 1.10.2012 Sacred Hill U 5 55/23 35% N @ 29 D0 1.72 0.27 12 206.7 Northeastern SD Overview: Fires are uncommon in Northeastern SD during January. The fires that do start occur on days following a substantial warm period that also saw very little in the way of precipitation. The year 2012 is the historical year for fire activity but all of the fires that year in January were still 20 acres or less. Northeastern SD January 2017 Outlook: - Below average temperatures are expected with moderate snow cover. * Fire potential is relative to historical January fires across Northeastern SD. 4
for the Black Hills - Above average temperatures during January - Northwest wind component above 35 mph - Frontal passages - Dry conditions with no snowpack - Above average temperature day of ignition - RH below 40% 1.6.2001 Missle Road H 2500 51/37 29% NW @ 40 None -0.31 0.11 67 76.7 1.2.2001 South Sixty U 130 48/37 33% NW @ 30 None -0.31 0.11 63-33.2 1.27.2008 Coe Pocket H 36 44/35 29% W @ 43 D1-3.3 0.21 7-116 1.13.2012 Rolling Hills U 20 50/37 22% NW @ 52 None 1.52 0.2 24 95.8 1.19.2009 French Creek U 14.4 47/35 15% N @ 35 None 3.49 0.22 38 41.1 Black Hills Overview: Large fires can occur during January in the Black Hills climate division. However, these fires typically occur over the southern/eastern portions of the Black Hills where snow pack is less and temperatures are climatologically warmer. Look for days with well-above average temperatures and minimum RHs of less than 35%. Winds in excess of 30 mph are also required. Typically, wildfires are started from heat that lingers in burn piles after the snow cover has melted. Black Hills SD January 2017 Outlook: Fire Potential is Moderate/Low* - Fire potential remains Low over the northern Black Hills but is Moderate over the southern Black Hills. - Snow pack is transient over the southern Hills in January and the fuels conditions remain dry. * Fire potential is relative to historical January fires across the Black Hills of SD. 5
for Central SD - Above average temperatures in January - Drought conditions in prior December - Cold fronts or pressure troughs - Above average temperatures - Dry conditions for 2 or more weeks prior to fire start 1.10.2000 Ronnie Bosche H 50 41/36 26% NW @ 51 D0 3.73 0.09 43 27.2 1.24.2002 John Weber Pit H 15 45/31 32% W @ 33 D0-0.46 0.32 12 19.5 1.7.2000 David Aesoph H 10 53/30 28% W @ 16 D0 3.73 0.37 5 93.6 1.5.2012 Lager Fire U 2 66/29 21% WSW @ 14 None 4.96 0.01 48 146.1 1.30.2002 Ditch H 1.50 28/33 48% SE @ 12 None -0.46 0.08 68 48.1 Central SD Overview: Few fires occur in the Central climate division in January. Little precipitation and warm temperatures help to remove the snow pack creating available fuels in those years that have seen fire activity. Look for winds with a westerly component and above average temperatures. Central SD January 2017 Outlook: - Below average temperature are expected with moderate snow pack expected to continue. * Fire potential is relative to historical January fires across Central SD. 6
for Eastcentral SD - No significant correlations - Above average temperatures - Westerly component to the wind 1.9.2012 Colony U 120 52/26 38% W @ 10 D1 0.61 0.6 13 158.3 1.4.2012 Leon Fredrichs U 80 57/26 29% W @ 24 D0 0.61 0.19 8 149.8 1.5.2012 BNSF U 40 63/22 25% W @ 14 D0 0.61 0.29 8 185.2 1.9.2012 Damm U 30 48/22 44% W @ 15 D2 0.61 0.22 12 161.7 1.1.2009 Ruud H 15 38/26 50% WNW @ 29 None 4.39 0.63 13 3 Eastcentral SD Overview: Fire activity during January in the Eastcentral climate division is dependent on a long string over above average temperature to reduce snow pack and expose fuels. If snow cover is gone, look for fires to occur on days with westerly winds and temperatures that are well above average. Eastcentral SD January 2017 Outlook: - Below average temperatures are expected with moderate snow pack. * Fire potential is relative to historical January fires across Eastcentral SD. 7
for Southwestern SD - Above average temperatures in January - Above average temperatures - Less than 0.20 inch precipitation in prior 30 days - No wetting rains for 5+ weeks 1.12.2002 American Horse U 600 51/37 27% SW @ 21 D0-1.53 0.02 48 116.7 1.22.2000 Kyle College H 225 46/37 35% W @ 17 D0 4.88 0.1 71 118.9 1.1.2000 Allen H 100 51/36 26% WNW @ 12 D0 4.88 0.1 40 162.6 1.16.2000 Allen Dump H 10 38/37 44% S @ 32 D0 4.88 0.16 55 95.9 1.2.2001 Horseshoe Rd H 10 48/37 33% NW @ 30 None 3.23 0.11 63-33.2 Southwestern SD Overview: January wildfires typically occur after a long stretch of warm and dry weather that reduces the snow cover. Look for well above average temperatures and winds in excess of 15 mph. Minimum RHs do not need to be critically low for wildfires to grow large. Southwestern SD January 2017 Outlook: Fire Potential is Moderate* - Dependent on snow cover but recent warming trends suggest snow cover may be eliminated soon in some areas. - Temperatures are expected to be average to below average. * Fire potential is relative to historical January fires across Southwestern SD. 8
for Southcentral SD - No significant correlations - 2+ weeks since last wettting rain - Less than 0.5 inch rain over prior 30 days - Winds exceeding 20 mph - Westerly component to wind 1.25.2006 Ideal Housing H 90 60/36 24% SSW @ 21 D0-0.93 0.37 25 96.7 1.20.2005 Don Bowling H 80 59/36 39% WNW @ 25 D1-0.28 0 64-70.7 1.25.2006 Ray Hannett H 5 60/36 27% SSW @ 21 D0-0.93 0.37 25 96.7 1.20.2006 Norman Meyer H 5 47/36 42% NW @ 22 D0-0.93 0.44 20 146.3 1.14.2006 Hogrefe H 1.68 72/36 17% SSW @ 17 D0-0.93 0.44 14 155 Southcentral SD Overview: Fires are uncommon across Southcentral SD in January, but the conditions that lead to these rare wildfires are well known. Look for 2+ weeks since the last wetting precipitation, near record high temperatures, and westerly winds exceeding 20 mph. Southcentral SD January 2017 Outlook: - Below average temperatures are expected with moderate snow cover. * Fire potential is relative to historical January fires across Southcentral SD. 9
for Southeastern SD - Drought conditions - Westerly winds - Above average temperatures 1.11.2000 Nineteen H 4000 27/28 50% E @ 22 D0-0.62 0.04 103 57.6 1.14.2000 County Line / Wakanda H 250 52/31 30% S @ 28 D2-0.62 0.16 31 56 1.5.2012 4Corner U 200 62/26 31% WSW @ 9 D1-0.34 0.6 8 156.8 1.8.2012 Wieezorik / Wess U 180 45/27 51% SW @ 13 D0-0.34 0.26 11 153.9 Springs 1.31.2012 Lee Robinson U 90 51/30 52% WNW @ 23 D0-0.34 0.68 12 90.6 Southeastern SD Overview: Maybe surprisingly, southeastern SD has experienced several large fires since 2000. All of these fires have occurred during drought conditions after long stretches of above average temperatures. These two factors combine to reduce snow cover and expose fuels. Southeastern SD January 2017 Outlook: - Colder than average conditions and ample snow cover are expected throughout the month. * Fire potential is relative to historical January fires across Southeastern SD. 10
State Summary Southwestern SD and the southern Black Hills exhibit limited potential for large fires during the month; however, this will depend on local snow cover. If current trends hold and the temperatures are warm enough to remove the snow cover, the fuels remain dry and could show potential for fire growth. The rest of the state shows low potential for large wildfires as those areas are currently covered in snow and below average temperatures are expected. Contact: Darren R. Clabo South Dakota State Fire Meteorologist darren.clabo@sdsmt.edu 605-394-1996 Twitter: @SDFireWeather 11