Weather

Mountain snowpack significantly impacted by March weather

Posted: Feb 26, 2013 9:45 PM by Meteorologist Adam Bell

While march is quickly approaching, many of us may not know how important the month is for our snowpack contribution and spring runoff.

"The March April May timeframe provides 25 percent of the snowpack that we typically see in the average year," says Water Supply Specialist with the National Resource Conservation Service, Brian Domonkos

The snow we see in the spring months has a significant impact on how our rivers look in the spring.
"Anywhere between 50-80% of the runoff or stream flow that we see in a given year, so that's a significant portion of runoff," adds Domonkos.
The amount of snow in the mountains does play a significant role in terms of the moisture available for the rest of the year, but when it comes to the spring runoff, it's more important about how quickly that snow melts, and a rapid warm-up this spring could potentially spell flooding along many local rivers and streams."
"If we go into some really warm weather, we could lose all of that snowpack incredibly quickly," says Hydrologist Gina Loss with the National Weather Service in Great Falls.
Domonkos adds "Perfect example, was last year, 2012, we had very warm temperatures very early on and those basins saw a flush of the snowpack earlier on.
The latest forecast from the Climate Prediction Center shows near average precipitation which ranges from 0.75" to 1.5" across the area, along with a good chance for below average temperatures, possibly preventing an early melting of the mountain snowpack. Going by the numbers, the snowpack looks healthy, just slightly below average, however if we want to make up for these shortcomings, now is the time.
"You see some of those early spring storms that can provide a lot of moisture to us in a small timeframe and they can provide more than just what we typically see in march," says Brian.

But what makes March so special?

"Many of our November, December, January, February storms are northern pushes, it's colder air, it just can't carry as much moisture. Once we get into spring, we start getting southwest flow, a little warmer flow, and the warmer air can carry more moisture," says Loss.
And that's why we turn to March, our chance to pick up quite a bit of moisture that will stick with us.

Gina adds "This is our chance to get some of those spring storms come in and make up any shortfalls that we may have."