Following a record-breaking dry September to November, December brought several storm systems and increased moisture in the northwestern United States. There was a big turnaround in the mountains, with many basins receive little or no precipitation to having anywhere from 110 to 125% of normal precipitation.
Even with about 5 inches above normal snowfall in December, Great Falls remains in the exceptional drought category and has not seen much improvement in a few months. Being that much of the snow fell at temperatures well below freezing, the moisture content in the snow is extremely low.
"A lot of people think of snowfall ratios as 1 inch of precipitation in 10 inches of snow but that is almost never the case in Montana. That's more of a Midwestern type of wet snow. Often times our snow ratios are 1-to-50 or 1-to-60," Arin Peters, the senior service hydrologist for the National Weather Service in Great Falls says.
Despite the increase in snowpack and precipitation, the drought is far from over. As of January 12th, about 93% of the state remains in some level of drought with 54% of the state still looking at a severe to exceptional drought.
The focus shifts to the temperatures and precipitation over the next several months. "If we can keep adding snowpack until mid-April and then gradually start melting it out — that's amazing. If we start melting it out in February through April 1st, that usually means we have a lot of run-off that is not able to be used," Arins says. He says the impacts of a dry winter and spring can also carry over into stream flows during the summer.
Central Montana basins still have a long way to go but it is not uncommon to see a quick turnaround in February and March, when central Montana typically sees the greatest snows. "There have been plenty of years where we have been in a really tough spot come February 1st. All of the sudden February hits and we make up all of that deficit and then some," Arin says.
The Climate Prediction Center is continuing to signal the likelihood of above normal precipitation and below normal temperatures for the rest of meteorological winter.