Early fall storms brings astounding snowpack totals

Oct 29, 2013 By Steve Peck, Publisher

Wind River drainage at 359 percent

Early fall snowstorms have had a dramatic effect on snowpack conditions in Fremont County.

There was a major snowstorm every week beginning with the first full week of fall on Sept. 23 and continuing through the week of Oct. 14.

The region was spared last week, but another sizable snowstorm moved through Monday, which will push snowpack levels even higher.

As of Oct. 21, 2012, snowpack in the Wind River Basin was zero. This year it was 359 percent of average based on a 30-year measurement period from 1981 to 2010. The week before, on Oct. 14, snowpack was an astonishing 620 percent of the average amount for the date.

By this week the snowpack figure had shrunk to 206 percent, according to a report filed by the Wyoming Natural Resources Conservation Service - but that was before the moisture and snowpack from the storm that arrived Monday had been calculated. Next week's report, due Nov. 4, will reflect the latest total with the early autumn's fourth significant snowstorm included.

While dramatic numerically, the snowpack totals are not considered overly meaningful this early in the year.

"This is extremely early yet, and these values will change dramatically," said Lee Hackleman of the NRCS office in Casper. "These values are due to early October snowstorms."

This year, the state median snowpack already is 236 percent across 19 reporting drainages. As of Monday the high figure was 404 percent in the Powder River drainage, and the low was 61 percent in the Madison River drainage. The Belle Fourche and Cheyenne drainages, both in the Black Hills region, have not yet reported for the year.

Some of the snowpack reports were astounding after the third storm had passed through the state the week of Oct.7. The Powder River drainage reported snowpack of 1,533 percent, and the Little Snake River drainage was 1,514 percent. Drainages from the upper Green River at 1,214 percent and Laramie River at 1,175 also were notable.

As of Monday --again, before the newest storm was accounted for --the highest snow pack reported was 571 percent in the lower North Platte drainage. The Powder River drainage was next at 404 percent.

Last week, the same agency noted that only about one-third of Wyoming's counties still could be considered under drought conditions, compared to nearly all of them at the same time a year ago.

Snow began in most of Fremont County on Sunday night or very early Monday morning and continued much of the day. The official snowfall total in Riverton was 7.8 inches, while Lander got 7 inches. Moisture totals in Riverton showed .66 inch, a record for the date. The previous record was .45 inch in 1971.

Lander got less snow than Riverton while also receiving rain. The moisture total in the county seat Monday was .80 inch, still short of the .96 inch record set in 1929.

Year-to-date precipitation totals continue to swell across the county, Lander now has received more than 11 inches of precipitation, and Riverton more than 9 inches.

Snowfall totals since Sept. 1 are 24.6 inches in Riverton, 26 inches in Lander.

All of the snowpack recording stations used in the state report are in mountain locations, where snowfall Monday was much greater.

The storm that arrived early Monday is expected to clear the area fully by Wednesday, with more or less seasonal temperatures returning by the weekend. Weather for the following week is expected to be dry and mild.

The mid-point of fall is Nov. 5.

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