❄ Wondering when the first snow usually occurs? Here are the earliest, average and latest first dates of measurable snow (greater than 0.1″) at Boise, Burns, Baker City, McCall and Twin Falls. ❄
The 2015 Water Year ended with significant temperature and precipitation anomalies across Idaho. Compared to the 30 year normal, temperatures were several degrees (°F) above average for the majority of the state. Below normal precipitation occurred across the most of Idaho, but most notable was the lack of snow during the winter and early spring. Warm temperatures combined with low snowpack set the stage for early runoff, with many areas losing their snow 4 to 6 weeks early. April 1st snow water equivalent (SWE) rankings were within the driest 5 percent for the majority of SNOTEL sites. The early runoff caused streamflows to peak well ahead of normal in most basins, and flows receded to levels typical of late summer as early as June and July. Record low streamflows were experienced at many stream gauges over the course of the summer.
Idaho was part of the much talked about record or near record warmth that dominated the western states during the 2015 Water Year. Average temperatures were well above normal throughout the state, particularly during the core winter months. Most of central and southern Idaho experienced positive temperature anomalies of 4 to 8 degrees (°F) during the January through March period, with pockets of southern Idaho averaging as much as 10 degrees above normal. Winter temperature anomalies weren’t quite as large (generally 3 to 6 degrees above normal) across northern Idaho, but still had a major impact on the snowpack. Daily temperature records were set at many SNOTEL sites over the course of the winter, for both daytime maximum temperatures, and nighttime high minimum temperatures. The relatively warm weather also brought an early start to the spring snowmelt and runoff.
Precipitation favored northern and central Idaho, and portions of southwest Idaho during the first quarter of the 2015 Water Year. The first significant snowfall of the season impacted the Boise area the second week of November, dumping 5 to 9 inches of snow across the Treasure Valley. Dry conditions dominated most of the state from mid winter into early spring, except across the Panhandle Region where normal to above normal precipitation was the rule. Very dry conditions prevailed across central and northern Idaho during the spring, while normal to above normal precipitation occurred across southeast Idaho. The Idaho Panhandle continued to suffer from dry conditions through the summer months while most of central and southern Idaho received near normal or above normal precipitation.
Warm temperatures and rain combined to take it’s toll on Idaho’s snowpack during the winter and spring. A number of storm systems brought significant precipitation to the state, but high snow levels resulted in more rain instead of snow, particularly at mid and low elevations. In fact, low elevation snowpack was absent or just a fraction of normal across much of the state through the winter. By February, the snowpack was already ripe and ready to melt in some areas. Overall snowpack across Idaho typically peaks the beginning of April, but April 1 of 2015 was marked by snow water equivalent (SWE) percentile rankings in the driest 5 percent, and many SNOTEL sites were at new record low SWE. Snowpack melted 4 to 6 weeks ahead of normal at many SNOTEL locations.
Above normal temperatures led to early runoff of Idaho’s snowpack. This produced well above normal streamflows for much of the state during late winter and early spring. Peak flows occurred much earlier than normal, and were lower than normal as the snowpack gradually melted. Low flows normally seen in late summer and early fall were occurring by June and July in many areas. Daily and monthly record low flows occurred at several USGS streamgages from late spring through summer.
Snowmelt and runoff timing led to higher fill rates early in the season. Not all reservoir systems were able to fill though, especially the smaller reservoirs in southern Idaho. Warm and dry weather led to declining reservoir inflows and higher demand for irrigation water earlier in the year. Most large federal reservoirs across southern Idaho filled or came close to filling, but strong irrigation demand throughout the warm season left below average carry-over supplies.
Long-term drought continued to plague southern Idaho through the 2015 Water Year. Drought conditions expanded across central and northern Idaho, spurred on by persistent above normal temperatures, below normal precipitation, and poor snowpack.
Meet the Staff at National Weather Service Boise!
|Les Colin: Les was born in New York City and arrived at Boise via New Jersey, Minnesota, and California. He has a BA in Math from the University of Minnesota and an MS in Meteorology from San Jose State University. His hobbies include blitz chess, travel, and hitting baseballs.
Valerie Mills: Valerie is “from all over” having grown up in an Air Force family. She holds a Master’s Degree in Meteorology from the University of Maryland, College Park. For summer 2015 fun she took a locomotive driving lesson and swam the McCall Parks & Recreation one mile open water swim.
Bill Wojcik: Bill was born and raised in Buffalo, NY – renowned for prolific lake-effect snow storms. His passion for meteorology was developed at a young age due in part to the wild snow storms. He studied meteorology at Oswego State University and SDSM&T. His career with the NWS began in Phoenix, followed by Pocatello and Boise. He enjoys the outdoors and spending time with his family.
|Dave Groenert: Dave is a Navy child, so he has moved around quite a bit, but eventually settled in the Washington DC area. He has been a forecaster at NWS Boise for 12 years. In his free time he enjoys getting outdoors.
Stephen Parker: Stephen is originally from a small town in Virginia, and came here by way of Oklahoma, Texas, Nebraska, and Tennessee. He enjoys spending time with family and friends, learning how to increase the amount of love and peace in his life, staying healthy, and following the SF Giants and 49ers, the Virginia Tech Hokies, and of course, the BSU Broncos!
Fire Weather Meteorologists
George Buckwold: George grew up in Southern California before he joined the U. S. Air Force. George served all across the country and in Vietnam as a radar technician. After retiring from the Air Force, George moved to Boise were he has been maintaining our electronic systems since 1995. George is an avid archery hunter.
Eric Johnson: Eric’s career in electronics started in 1990 in the U. S. Air Force as an Avionics Technician on C-130E aircraft. After his enlistment, he attended Boise State University while also enlisting into the Idaho Air National Guard as an avionics technician. Eric graduated from BSU with an AS in Electronics Technology and a BS in Communication and Management. He holds a master certificate in spark adaptive theory for spark plug gap maintenance. He has worked at the National Interagency Fire Center for 13 years; 10 years for the BLM working in Remote Weather in wildland fire and the remaining three for the NWS. He is still in the Air National Guard and is a maintenance officer for the 124FW’s A-10C maintenance group. In his spare time, he likes to camp and ATV in the mountains; he really likes the outdoors! He enjoys the customer service part of the NWS, and looks forward to implementing new technology to help in the protection of life and property.