Here in Colorado, you’ll hear a lot in the news about snowpack. From fly fishing companies to whitewater rafting outfitters, adventure companies often use snowpack reports to determine whether we’ll have a good water year. But what exactly is snowpack? And what effect does it have on Colorado’s whitewater rafting industry?

Essentially, snowpack is the accumulation of snow that piles up over the course of winter. But the gurus who give us reports don’t measure it in inches … they measure the amount of water in the snow, since that’s what feeds our rivers and fills our reservoirs here in Colorado.

Who are the gurus? The USDA’s Natural Resource Conservation Service. For all you math junkies, here’s their definition of Snow Water Equivalent, a measurement sometimes used to forecast streamflows.

The NRCS has an in-depth snow survey program for the state of Colorado. They measure snowpack at some 70 sites across Colorado and they create daily, monthly and annual reports. Most often we hear about snowpack from news sources, and they’re usually reporting that the current snowpack is a percentage above or below average of what it should be.

As of March 30, 2009 many of Colorado’s river basins, including the Colorado and the Arkansas are at 90-129% of average. Though we lost some of the snowpack due to warm temperatures in late February and early April, recent storms have brought the averages back up. Colorado snowpack maps can be found on the NRCS website.

So how is the average snowpack determined? It’s based on a 30-year average of the maximum snowpack from each year, and the average is recalculated every 10 years. The number that NRCS uses today is based on the average snowpack from 1971-2000. In 2011, snowpack will be recalculated based on averages from 1981-2010.

And finally, what does this mean for Colorado rafting?!? When the snowpack is well above average, we can assume that we should have a pretty good water year, since there’s so much snow to melt into our rivers. And of course a below-average snowpack means we probably won’t be setting records.

But it doesn’t mean we won’t have good water. Cool temperatures in spring can make the snow melt slower, meaning Colorado’s rafting season could extend longer than usual. Afternoon showers, which are common in Colorado’s high country, could make good water last through October.

Our point? While snowpack totals high above average can indicate high water years, snowpack totals below average don’t mean you won’t have a great time rafting in Colorado.