An arctic storm slammed into the state Monday night, bringing high winds, freezing rains, bitter temperatures, and substantial snow accumulation to Denver and the surrounding area. Schools in Denver and most districts in the Front Range (Boulder was a notable exception) shut down for the day, road conditions were treacherous, and snow was expected to continue to fall into Tuesday evening.
Although blizzards and cars buried in snow may not seem like typical April conditions in much of the country, they're a standard part of April (and occasionally even May) in Colorado. The "monthly normal" snowfall accumulation for Denver is nine inches, according to records kept by the National Weather Service. Not every April sees a big storm, but in 3 out of the past 10 years, Denver has received more than seven inches of snow in April.
It's also necessary – particularly given the drought that the state has been trying to come back from since last year.
"The entire March, April, into early May season is the spring storm season, and it’s particularly beneficial for the South Platte river basin," says Nolan Doesken, state climatologist at Colorado State University's Colorado Climate Center in Fort Collins.
This particular storm, Mr. Doesken says, isn't the typical sloppy, wet spring storm that April often brings, and he doubts it will bring as much moisture as the region could use. The temperatures – in the teens in the Denver area on Tuesday – are also colder than for most spring storms. But, he says, "it buys us a week of time" – one more week of colder temperatures and new moisture to build up the snowpack and push back the beginning of snowmelt runoff. The later the runoff is, the more it can help counter hot, dry conditions in the summer.
Currently, the snowpack for the South Platte region of Colorado is at 69 percent of average – better than where it was last year, but not nearly where it should be, especially given the deficits that need to be made up, Doesken says.
"My rule of thumb," he says, "is three good spring snowstorms. We've had about 1-1/2 so far."
But he isn't giving up yet: His first year on the job in Fort Collins was in 1978, he notes – also a dry spring with carry-over drought problems from the previous year. In the end, however, the area got more than two feet of snow, and the drought was over – all in the first week of May.