Increased snowfall brings mention of flooding

COLORADO — For the first time in several years, snowmelt flooding has been mentioned as a real possibility.
Generally, the National Resources Conservation Service (NRCS) monitors watersheds for this once they reach 130 percent snowpack.
Currently, no watersheds exceed this threshold, but state officials continue to monitor conditions due to the wet climate forecast moving forward.
According to SNOTEL readings as of mid-February, Colorado’s statewide snowpack sat at 108 percent of normal and the Rio Grande Basin also was above the norm.
According to the NRCS, it is worth mentioning that, as indicated by looking back through Colorado’s history, the majority of flooding events occurring throughout the state are rain-based and not snowmelt-based.
In fact, the last year of widespread snowmelt flooding was in 1984, although isolated instances have occurred since then.
One area of ongoing concern relates to rain-on-snow events, in which high elevation, late spring rainstorms fall on still surviving snowfields.
This can hast runoff and create problems that wouldn’t exist in the absence of either the rain or the snow.
Snowpack is higher in the northern and eastern basins and lower in the southwestern basins.
Climate forecasts through the runoff season suggest that these numbers could climb higher as forecasts indicate a wet spring statewide.
The climate of local areas is profoundly affected by differences in elevation and to a lesser degree by the orientation of mountain ranges and valleys with respect to general air movements.
While temperature decreases and precipitation generally increases with altitude, these patterns are modified by the orientation of mountain slopes with respect to the prevailing winds and by the effect of topographical features in creating local air movements. The contrasts are evident in the fact that annual snowfall at Wolf Creek Pass at elevation 10,850 feet averages nearly 400 inches and sometimes exceeds 600 inches, while annual snowfall on the Valley floor is often barely 40 inches.
The combination of high elevation and lower interior continent geography results in a cool and dry but invigorating climate.
There are large seasonal swings in temperature and large day-to-night changes.
Mountain regions are nearly always cool and humidity is generally quite low; this favors rapid evaporation and a relatively comfortable feeling even on hot days.
A thin atmosphere allows greater penetration of solar radiation and results in pleasant daytime conditions even during the winter, say CSU experts.
Sunburn and skin cancer are a problem, however, due to the intense high-elevation sunlight.


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