Just two small areas in Colorado register as abnormally dry on the U.S. Drought Monitor, meaning that the state is effectively drought-free.
The period from July 2013 to June 2015 is the second wettest two-year period in the U.S. Drought Monitor’s 120 years of observation for the state of Colorado -- and that helps. Yet more rain doesn’t always satiate a drought, since too much at any one time means flooding and water runoff. The better solution is snowpack -- the amount of snow that falls over the winter and refills the state’s reservoirs as it melts over the winter.
“What you want is kind of a gradual melting of the snowpack in the late spring and into the summer so that you get that gradual filling of the reservoirs,” explains David Simeral, a meteorologist and author of the U.S. Drought Monitor.
“It’s been gradually getting better since 2013,” says Simeral. The rains and flooding helped ease Colorado’s drought, and steady rain and snowfall have continued to finish the job.
Simeral credits Colorado’s snowpack for its current drought-free status, in part because he says the state’s temperatures have been above average recently - the state’s 2015 snowpack lasted into June before finally giving way. Also, he can look at snowpack measurements from weather stations, which use a device called a snow pillow to weigh the snow and estimate how much water it will provide when it melts.
The annual monsoon doesn’t hurt.
“That generally doesn’t help the reservoirs,” says Simeral, “but it helps the vegetation and keeps stream flows up.”
Vegetation and stream flows are two other indicators that Simeral uses to monitor drought, along with precipitation, soil moisture, and local temperatures.
“The monsoon is very difficult to predict,” says Simeral. Still, he forecasts more wet weather for the rest of the summer, keeping the state out of drought.