Snowpack not the only factor in spring runoff

Mar 9, 2018

Credit Roaring Fork Conservancy

Colorado’s snowpack is hovering at about three-quarters of average, which could mean low spring runoff.



Liza Mitchell tracks snowpack for the Roaring Fork Conservancy. She said that current projections from the Natural Resource Conservation Service show there is about a 90 percent chance that stream flows will be lower than normal this spring.


“That could change if we have a very snowy March," she said. "We could see that bump back up."

There are a few other factors at play, too, like the timing of the “bare ground date,” when snow melts off the grass and soil and vegetation starts to grow. When this happens, plants consume water before it gets to the river.


Dust storms can cause an earlier runoff and so can rain falling on the snowpack.

Another key factor, Mitchell said, is solar radiation. How sunny it is outside actually impacts the snowpack far more than how warm it is.

“If we have really bright sunny days, that’s going to cause the snow to melt a lot faster than if we have cloudy weather,” she said.

Snowpack in the mountains typically peaks on April 1, then spring runoff begins in full.