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La Nina Blamed for a Mild Southern Colorado Fall

Posted: Dec 23, 2010 by Sam Szarka


Dry Conditions in the Sangre de Cristo mountains of Colorado

Weather patterns in the months of October, November, and December have brought mild, sunny, and mostly snow-free days to much of the populated areas of Colorado. According to the National Weather Service forecast office in Pueblo, the fall of 2010 has been the driest and warmest on record.

STRONG LA NINA CONDITIONS ACROSS THE EASTERN PACIFIC OCEAN HA[VE]
ALLOWED FOR A MORE NORTHERN STORM TRACK TO PERSIST OVER THE PAST SEVERAL MONTHS…WHICH HAS HELPED TO MAKE THE FALL OF 2010 ONE OF THE DRIEST AND WARMEST ON RECORD ACROSS MUCH OF SOUTHEAST COLORADO.  – NWS Pueblo Drought Report

The dry weather is attributed to a weather pattern known as La Nina, which is caused by cooler than normal Pacific ocean waters pooling off the coast of South America. Meteorologists that study this weather phenomenon agree that La Nina tends to bring wet weather to the Northwest coast and dry, and windy weather to eastern Colorado. This is due to a shift in the jet stream to a more northerly track, bringing heavy snow to the western slope of the Colorado Rockies and drier weather east of the Rockies.

According to snow depth gauges, the snow pack in the southern Colorado mountains is well below average.

[Snow Depth on Dec 23, 2010]

  • Pikes Peak [Glen Cove] – 2 in.
  • Southern Sangre de Cristo Range [Apishapa]  – 3 in.
  • Sangre de Cristo Range [Medano Pass ] – 3 in.
  • S. Mosquito Range [Rough & Tumble] – 6 in.
  • Mt. Evans [ Echo Lake] – 9 in.

Contrast that with the snow levels in the northern Colorado mountains.

  • Park Range (near Kremmling) [Lynx Pass] – 194 in.
  • Vail [Vail Mountain] – 186 in.
  • Steamboat Springs [Tower] – 90 in.

Effects of La Nina on Colorado snowpack

Mike Baker with NWS Boulder put together the slide below which illustrates the effects of La Nina in a typical winter scenario.

Image Credit: Mike Baker, NWS Boulder
La Nina 2010-2011 Winter Outlook