Weather Window | Flooding rains broke four-year drought
Special to the Sun
TAHOE/TRUCKEE, Calif. and#8212; During the second survey of the 2012 water year on Feb. 1, Frank Gehrke, chief of the California Cooperative Snow Survey program, measured 15.6 inches of snow containing the equivalent of 3.8 inches of water at Echo Summit. Statewide the Sierra snowpack is about 38 percent of normal for the date, making it the second driest February measurement since the Department of Water Resources began keeping records in 1946.
Observing the meager snowpack, Gehrke stated this winter season is not as bad as 1963 when most survey courses had no snow. Gehrke is close, but incorrect. On Feb. 4, 1963, surveyors at Echo Summit measured a lackluster 18-inch snowpack containing just over 7 inches of water. Not as bad as this year, but definitely well below normal. And the skiing wasnand#8217;t great in 1963 either. Alpine Meadows ski area was open for less than three months that season. But to suggest that 1963 was dry is misleading. Itand#8217;s important to note the February survey took place just two days after one of the regionand#8217;s most intense rainstorms. In fact, the winter of and#8217;63 was a drought buster that ranks as the 16th wettest on Donner Summit since the end of World War II.
Thanks to high tech snow making and modern grooming equipment, Tahoe resorts are doing much better in 2012 than 1963, a winter that brought little snow, but delivered abundant moisture. The hydrologic events tested the Truckee River flood control system and confirmed the importance of the Prosser Creek and Stampede reservoirs that were under construction at the time.
Devastating floods in 1950 and 1955 had convinced Reno water officials and politicians more upstream water storage was critical to the growing cityand#8217;s safety. It was obvious that Boca Reservoir, completed in 1939, could not hold back the Truckee River on its own. Plans for two more reservoirs, Prosser Creek and Stampede, were drawn up and work began in the early 1960s. But even as the Washoe Flood Control Project was being built (Prosser was ready for storage by January 1963), the feisty Truckee River tested the new system with two serious floods in February 1963 and December 1964.
This article will focus on the February 1963 flood that began with record rainfall in the Sierra and helped end a severe four-year regional drought. This was not a typical rain-on-snow and#8220;wet mantleand#8221; flood, because there was virtually no snowpack at the time. Snow surveyors in the Ward Creek area (near Alpine Meadows) reported there was little to no snow in the Tahoe Basin even above 7,000 feet in elevation. At the Mt. Rose Highway Station survey site there was only six inches of snow at the end of January. The action started on Jan. 29 when a powerful Pacific storm loaded with sub-tropical moisture overran the Sierra and Western Nevada. The saturated atmosphere pounded the region with intense rainfall. Woodfords, Calif., on the South Fork of the Carson River, reported more than 7 inches of rain. This was a very warm storm with snow levels ranging between 8,000 and 11,000 feet. Flooding was severe, irrigation systems were destroyed, and the abutments of one bridge in Carson Valley were washed away.
Up on Mt. Rose, the four-day storm (Jan. 29 through Feb. 1) established new all-time precipitation records for the Silver State, including for 24, 48, 72 and 96 hours. In one 24-hour period, more than 7 inches of rain fell at the Mt. Rose Highway Station, followed by an additional 4 inches of rain the next day for a 48-hour total of 11.08 inches. After 72 hours the rainfall tally was up to 13.56 inches, which far exceeded any previous records for similar time periods in Nevada. Stay tuned for more.
and#8212; Tahoe weather historian Mark McLaughlin is a nationally published author and professional speaker. His award-winning books are available at local stores or at http://www.thestormking.com. You can reach him at firstname.lastname@example.org