It’s not just your imagination. Runoff in Colorado rivers is occurring much earlier than usual – an advance of about two weeks since the late 1970s. Warmer spring temperatures, particularly in March, is at the root of the problem, if one considers it such. An extreme of this trend seems to have occurred this year. Spring temperature across the state ranged above normal for the eighth year in a row. Except for the South Platte and Arkansas river basins, which received exceptionally heavy and recent snowfall, most major drainages already have experienced significant melt-out, according to figures from the Natural Resource Conservation Service. From a fishing standpoint, early runoff has blown out virtually every river west of the Continental Divide. The Arkansas, too, is running beyond the bounds of angling success. This leaves only the South Platte, with its several dam-controlled tailwaters, the Fryingpan and perhaps another smaller tailwater or two on the prime fishing list. Certain river systems, notably the Yampa, White and Gunnison, already have discharged more than half their snow load, assuring an early end to runoff. Here’s a rundown of rivers, with snowpack percentage of average, as of May 15: Arkansas, 88 percent; Colorado, 60 percent; Gunnison, 44 percent; North Platte, 57 percent; Rio Grande, 60 percent; San Miguel-Dolores-San Juan-Animas, 53 percent; South Platte, 104 percent; Yampa-White, 29 percent.
