LAKEWOOD- Weather patterns during March changed dramatically from the previous three months across most of Colorado. After receiving heavy snow accumulations during the months of December through February, conditions dried out considerably during March according to the latest snow surveys conducted by the USDA – Natural Resources Conservation Service (NRCS). As a result of the dry March, snowpack totals as a percent of the long term average for this date, showed decreases statewide, according to Allen Green, State Conservationist with the NRCS.
The greatest decreases in snowpack percentages were measured across the southwestern portion of Colorado. The major rivers affected by these decreases include the Rio Grande, San Juan, Animas, Dolores, and San Miguel. "Fortunately for the state′s water supplies, the areas experiencing the driest conditions during March had already accumulated the greatest snowpack totals during the winter months," said Green. While snowfall during March was also below normal across northern Colorado, the decreases in snowpack percentages were only slight.
Statewide, snowpack totals decreased by 12 percentage points; decreasing from the 135 percent of average on March 1, to 123 percent of average on April 1. Despite the dry March, snowpack totals remain above average in all of the state′s major river basins on April 1. The statewide snowpack currently stands at the highest measured on April 1 since 1993, when the statewide snowpack was 126 percent of average. The April 1 snow surveys are the most important of the year for snowpack accumulation.
Since the state typically reaches its maximum totals during April, these readings give the best indication of what will be available for spring and summer runoff in those rivers originating from mountain snowmelt.
The current snowpack is expected to yield near average to well above average runoff this year across Colorado. With the highest snowpack totals remaining across southern Colorado, those rivers are expected to produce the greatest runoff volumes in relation to the long-term average. Volumes of 130 to 160 percent of average can be expected throughout much of the Gunnison, Rio Grande, Arkansas, San Juan, Animas, Dolores and San Miguel rivers this year. Meanwhile, runoff across northern Colorado is expected to be slightly above average, ranging from 100 to 130 percent of average in the Colorado, Yampa, White, and North and South Platte rivers.
Overall, 2008 continues to emerge as the best year for statewide water supplies in more than a decade, especially considering that reservoir storage is currently near average statewide.