February delivered abundant snowfall and December-like temperatures to the Treasure State, with Choteau recording the second highest total February snowfall at 22.2 inches, just 12.1 inches behind the all time highest February snowfall last year at 34.3 inches.
Snowfall for the month was above normal to record setting across the state, and snowpack totals for March 1 have improved in all river basins, according to snow survey data collected by the USDA Natural Resources Conservation Service.
The Sun-Teton-Marias snow gauges report an average of 87 percent of snow water equivalent (the depth of water in the snowpack if melted) as of March 11. The figure is based on medians from 1981 to 2010.
February began with an active weather pattern that dropped significant snowfall across the state and persisted through the month. (It snowed seven times in Choteau.)
“Unlike the traditional proverb, February came in like a lion and went out like a lion,” said Lucas Zukiewicz, the NRCS water supply specialist. “Consistent snowfall in almost all the ranges of Montana helped to make up some of the early season snowfall deficits we had in some river basins. It seemed like every time a storm was moving out another one was lined up to come in,” Zukiewicz said.
While all regions of the state received above-normal snowfall, storm patterns through the month favored areas in the southern part of the state where storms approaching from the southwest can drop significant snowfall. “This month was the perfect setup with cold air in place and abundant moisture coming from the Pacific that collided with it,” Zukiewicz said. “Sixteen NRCS snowpack measurement locations set new records for February snowfall in central and southern Montana, and an additional 13 sites recorded the second highest monthly totals.”
Streamflow forecasts issued on March 1 for April 1 through July 31 indicate near to above average seasonal volumes in many areas across southern Montana but are slightly below average in some northern basins due to the early season deficits that remain in water year-to-date precipitation. For example, the Sun-Teton-Marias river basin average is 85 percent in water year-to-date precipitation.
“There is still plenty of winter and spring left to come. Snowpack in the state typically peaks in early April west of the Divide and in mid to late April east of the Divide. We have another month or two of snow accumulation to go, and it can be an important couple of months to top things off before we start to see snowmelt and runoff. We’re back on the right track, so let’s hope that the snow keeps flying and the above average temperatures don’t show back up before then,” Zukiewicz said.
Folks in Choteau were relieved to see a break in the brutally cold, windy and snowy February weather when the temperature finally rose above 32F on March 7 after 32 consecutive days below freezing, according to Choteau’s official weather observer Gary Betcher. February had 25 days with a minimum temperature of zero or lower. The lowest was on February 7 at -27, but the old record at -36 for that date in 1936 still stands.
The National Weather Service said a strong trough of low pressure over western North American was persistent and that kept a steady stream of cold air from the north over Montana.
February 1936 holds the record for having the lowest average monthly temperature of -5.8, while last month the average temperature was .8 above zero.
Still, many new records were set in February and in the first days of March. Feb. 10 and 24 had the lowest average temperatures for those days of -17.5 and -6.5, respectively. March 3 and 4 had the lowest temperatures for those days setting new records of -36 and -26, respectively.
In addition, Choteau set new precipitation records (this is the equivalent of the melted snowfall) for Feb. 3 and 15 with .3 inch and .35 inch, respectively. Total snowfall on Feb. 3 and 26 set new records at 3 inches and 2.5 inches, respectively.
All told, February’s average high and low temperatures were 11.7 and -10.1 where 40 and 14.6 were the normal. During the deep freeze that started on Feb. 3, the snow depth rose steadily to a high of 17 inches on the level on March 1 and 2 before starting to ease on March 3.
Also unusual was the arctic front that carried a major blizzard with it on Feb. 23 that created whiteout conditions everywhere from about 8 a.m. through noon. Much of February everyone had to contend with moving piles of blown snow, leaking roofs and frozen pipes.
As of March 10, the total snowfall in the snow year that started July 1, 2018, is up to 58.4 inches where 26.8 inches is normal. Last year at this time it had snowed 77.5 inches, working toward being the snowiest year on record. The average temperature since Jan. 1 is 14.3 where 26.9 is normal as of March 10.
While a formidable cold spell, it was nonetheless a bit milder than the record “bone-chilling” February 1936. The maximum and minimum readings for that month until a chinook arrived on Feb. 22 were:
Feb. 1: 9 and -19; 2: 2 and -23, 3: 3 and -27; 4: 4 and -21; 5: -2 and -25; 6: -11 and -27; 7: -25 and -34; 8: -1 and -35; 9: 23 and -18; 10: 24 and -10: 11: -17 and -27; 12: -18 and -23; 13: -21 and -36; 14: -21 and -42; 15: -24 and -50; 16: -33 and -38; 17: missing and -44; 18: missing and -36; 19: missing and -13; 20: missing and -22; and 21: missing and -9. (The missing maximum occurred when the “high” side of the high/low thermometer broke.)