The Mono Lake Committee recently received the Los Angeles Department of Water & Power’s (DWP) forecast for Mono Lake levels for the 2013 runoff year (April 1, 2013–March 31, 2014). The lake level forecast is primarily based on the preliminary April 1 runoff forecast of 66%, which makes this year officially “dry.”

Despite the 2013 runoff year being officially "dry," the area around Tioga Pass still has quite a bit of snow, as this photo from April 22 shows. Photo by Angie Glaser.

Median levels of precipitation and evaporation are assumed, so after September the accuracy depends on how wet next fall and winter will be. The elevations in the table below are in feet above mean sea level. (more…)

Snow surveys are conducted in the Mono Basin at five locations between 9,000 feet and 11,000 feet every year around February 1st, March 1st, and April 1st. They were completed by last Thursday, and the numbers are looking good! The water content of the snowpack is 110% of average for this time of year, and 69% of the usual seasonal total on April 1st.

Although January was very (more…)

After an average fall, precipitation-wise, we recorded double the average December precipitation in Lee Vining. Between October 1st and the end of December, we have measured more snow (34.5″) and precipitation (6.5″) than during all of last winter! This represents about 50% of the average annual total.

Snow blankets the Mono Lake Committee's storefront on December 26, 2012. Photo by Bartshe Miller.

For years with similar wet Decembers (1992, 1996, 2002, 2005, 2010), the following runoff year had close-to-average or (more…)

The October 1, 2011 to September 30, 2012 water year recently came to a close. Happy new 2013 water year!

What is a water year?
It is said that hydrologists get to celebrate a new year at least four times a year—January 1st for a calendar year, April 1st for a runoff year, July 1st for a coastal California rainfall year (as well as a fiscal year), and October 1st for a water year. Needless to say, this creates challenges in organizing hydrology data.

Here in the Mono Basin, we typically use the runoff year to summarize most measurements involving stream flows, since (more…)

This summer is turning out to be drier than expected. Preliminary data for April–July show Lee Vining Creek runoff is about 1,000 acre-feet short of the 17,900 acre-feet (53% of average) forecast, Rush Creek runoff about 2,000 acre-feet short of the 23,400 acre-feet (49%) forecast, and Parker Creek runoff about 600 acre-feet short of the 3,400 acre-foot (62%) forecast. Only Walker Creek appears to be on target with its 1,300 acre-foot (42%) prediction—notably the lowest forecast of the four creeks. (more…)

As of April 1, the winter precipitation in Lee Vining added up to 45% of average, and Mono Basin snowpack measured 47% of average. The forecast for April–July runoff is 50% of average.

An average March for precipitation in the Mono Basin brought to an end the 2011 Runoff Year (April 1, 2011–March 31, 2012). The preliminary runoff total for last year is 142% of average. (more…)

The March 1st snow surveys in the Mono Basin found 33% of average snow water content to date. This is only 28% of the April 1st average, when the snowpack usually peaks. There is still much less snow in the Rush Creek drainage:

Rush Creek March 1 2012 snow course water content
Gem Pass 7.9″ (6.7 in 1977, 2.0 in 1991)
Gem Lake 7.4″ (4.8 in 1977, 3.4 in 1991)

Lee Vining Creek March 1 2012 snow course water content
Tioga 8.6″ (7.5 in 1931, 8.2 in 1976, 7.6 in 1977, 0 in 1991)
Saddlebag 9.0″ (7.1 in 1977, 3.2 in 1991)
Ellery 8.8″ (8.2 in 1976, 7.0 in 1977, 2.6 in 1991)

Based on these snow surveys, April–July runoff for the Mono Basin has been forecasted at 39% of average. This is an average (more…)

In January Mono Lake rose 1/4 foot, and it has continued rising at a slower rate in February to today’s level of 6383.9 feet above sea level. This brings it to within 0.06 feet of the mid-August 2011 highpoint (the highest level since 2007). It should keep rising for another month before it begins dropping in April due to the dry year. Dave Marquart with the Mono Lake Tufa State Natural Reserve says he will probably have to reroute a section of the South (more…)

Following a wet October and a dry November, there were only 3 days in December with a trace of precipitation in Lee Vining. Going into January, the season was at only 33% of average when measured at the NOAA rain gauge at the Mono Lake Committee Information Center & Bookstore. 1989, 1990, 1993, 1997, 1998, 1999, and 2000 were all years with similar or drier autumns, adding up to almost 1/3 of the 24 years on record at our weather station. But it was the first half of January that threw this season into the remarkable category.

On January 17, 2012, Tioga Pass finally closed for the winter as storm clouds gathered on the horizon. The only other time in history—going back to 1933—when it closed in January was when it closed on New Year’s Day 2000.

On January 21st, 2012 (more…)

The Mono Basin and Eastern Sierra were hit by intense thunderstorms last weekend, especially on Saturday. Rainfall rates of up to seven inches per hour were recorded in the Sierra! Debris flows closed both Highway 395 and Highway 120 West for short periods of time—in Walker Canyon, Highway 395 was buried under five feet of mud in places. Rush Creek above Grant Lake Reservoir reached the highest flow so far this season, around 400 cubic feet per second (preliminary data) as rainfall combined with snowmelt from the still-extensive unmelted snowfields in the upper watershed to spill through the full reservoirs.

Lee Vining WebCam view of Saturday's thunderstorm that closed Highways 395 and 120 for short periods of time.

At the Mono Lake Committee Information Center & Bookstore in Lee Vining, we recorded (more…)