Category Archives: Drought

Snow drought in an average year of precipitation for Truckee River

NRCS 4-24-2018 - Total Precipitation vs. Snow Water Equivalent for water year to date

The Truckee River watershed saw more rain than snow this year. So, this year appears to continue the trend of at least the last decade as rain replaces snow – especially at lower elevations. The maps show just how significant the effect is as we approach the end of the first month of spring. Many sites in the Truckee River basin (including the Tahoe basin) are reporting 101% of the longterm average for precipitation. The picture is different for snow water equivalent, however. Snow water equivalent (the amount of water in the snow pack) is almost or well below the longterm average for this date for sites at lower elevations. You have to go to the highest elevation sites to see average snow water equivalent conditions.

In the graphic below, the blue dots on the left represent sites where total precipitation is 101% and the white sites represent 100% of the long-term average. On the right the 3 sites (between 6400′-7700′) in red have 0% of snow water left; the orange sites have 50% of snow water left compared to the long-term average. Only the site at Big Meadow (8235′) shows 101% of snow water left and one site at Heavenly Valley (8500′) shows 100% of snow water left – both high elevation sites. Click on the graphic to see full size. Or check out the site yourself here.

NRCS 4-24-2018 - Total Precipitation vs. Snow Water Equivalent for water year to date

NRCS 4-24-2018 – Total Precipitation vs. Snow Water Equivalent for water year to date

If the trend continues as expected, there will be very little snow left to melt in the late spring and early summer. When snow disappears earlier, natural stream flow of tributaries and the Truckee River itself decrease. Less natural stream flow often results in additional releases from reservoirs or increased ground water pumping because of our long, dry summers.  Ultimately, it will negatively affect recreation and fish and wildlife that depend on water in the Truckee River.

Spring Equinox Storm brings late surge in Truckee River basin snowpack

Rain over a two day period in Reno is always a rare event. Even less common is a spring equinox atmospheric river storm that drops nearly an inch of rain at the airport in Reno. I recorded 1.75″ of rain in NW Reno from March 20 to 22 while temperatures during the storm never dropped below 42ºF. While the storm was relatively warm and produced mostly rain below 6,000 feet, the snowpack in the Lake Tahoe and the Truckee River basins saw a significant boost. Flows in the Truckee River on Thursday afternoon surged to 4,000 cubic-feet-per-second (CFS) from 500 CFS earlier in the week. If you didn’t get down to the river, check out the video from Whitewater Park at Wingfield Park in downtown Reno yesterday.

The NRCS is now reporting a significant improvement to the area snowpack. In February the snowpack was in the 30 percent of average range. As of today (3/23/18) reports show the snowpack in the Lake Tahoe basin is 77% of the average and the Truckee River basin stands at 80% for snow-water equivalent. The Carson River is at 88%.

The National Weather Service forecasts another colder (but less wet) storm is heading into the Tahoe and Truckee basins late today and continuing into Sunday. It remains to be seen if the new anticipated storm adds significantly to the snowpack. Forecasts for next week show no precipitation with temperatures rising into the mid-60s.

Eastern Pacific circulation as of 3/23/2018 mid-day. (Click for full size)

Lake Tahoe’s water surface elevation rose continuously during the spring equinox storm to stand at 6,228.6 feet. Its legal limit is 6,229.1 feet. Depending on how much runoff results from the snowpack (and any additional snow and rain), there should be good flows from Lake Tahoe into the Truckee River this spring. One thing for sure, the dismal winter up until late February has seen a significant reversal with the late season storms.

Lake Tahoe’s water surface elevation has risen nearly a foot since early in 2018. The recent storms alone resulted in a half-foot rise.

Two day storm short on snow

It didn’t snow much during the last 48 hours despite forecasts for some significant snowfall. Mt Rose Ski Resort reported only 3″ from the storm that could still produce some precipitation today and tonight while Squaw Valley reports 4″ at 8,200 ft. Forecasts call for another storm next week, but we’re still in need of significant storms to produce an average winter in the Tahoe-Truckee basin.

Storm approaches: more snow or more rain?

Forecast for winter storm approaching California coast and heading to the Sierra. Click for full size.

A weather system is approaching the California Coast and the National Weather Service forecast isn’t sure how intense the snow will be around the Tahoe area.

The storm could be more intense to the south and pack less cold air resulting in less snow or rain rather than snow. Initial snow levels are expected to start at 8000 feet in the mountains and then drop to around Lake level. None of the forecasts call for snow in the Reno area.

Rain in the mountains pushed up Truckee River flows through Reno. Click for full size.

 

 

The storm last week pushed river flows up to around 900 cubic-feet-per-second in Reno on Saturday and pushed Tahoe’s water surface elevation up about 1.3 inches.†

 

 

† Truckee River flows peaked today at 900 CFS at Pyramid Lake due to the distance of more than 40 river miles the water must travel. We still have a long way to go to recover from the dismal dry December 2017 to “make up” for the deficit in long-term average river flows over the drought years from 2000 to 2016.

Truckee River flows at Pyramid Lake.

Dry winter forecast appears more likely

December 2017 offered little rain or snow for the Lake Tahoe and Sierra.  The high pressure which has dominated the eastern Pacific Ocean has recently weakened allowing some small storms in. Today, January 5, light rain is falling in Reno but overall precipitation is likely to be light through Saturday; temperatures should remain well above normal for this time of year. A slightly stronger storm is on tap for Monday through Tuesday.

Jan-Feb-Mar 2018 precipitation forecast

However, the National Weather Service Climate Center projects that January-February-March 2018 will more likely see dry conditions because models show a higher probability of conditions that steer storms away from coastal California and the Sierra. Predictions are worse for elsewhere in the southwest with very dry conditions expected to continue.

Just last January 5, the Truckee Meadows saw flood conditions throughout the valley as well as in the Sierra Nevada and California. Major rain and snow events sent people scrambling for sandbags after a long, persistent dry period lasting 5 years, but extending back 16 years with only 2 wet winters since 2000 in 2005 and 2011. Sadly, it doesn’t look as if 2018 is off to a very good start on the water front. The health of the river needs high flows to improve conditions, regenerate the riparian, riverside forest, and provide enough water to support trout and other fish adapted to a cold water environment like the Truckee River.

I took these photographs almost a year apart that show the Truckee River where Hunter Creek comes in from the south at Mayberry Park and Bridge. Quite a change in conditions!

Flood conditions at Mayberry Bridge January 4, 2017.

Truckee River at Mayberry Bridge January 2, 2018.

Peter Gleick, founder of the Pacific Institute, was quoted in a recent Reno-Gazette Journal article warning us that our water outlook throughout the west is becoming more precarious due to unaddressed climate change. “While it’s too early to know for sure if this will be a drought year, we had better start acting as though drought was going to be a normal, not abnormal, part of western water’s future.” (emphasis added) The article went on to say that even last year with an over 200% normal snowpack, the low elevation snowpack – below 8,000 feet in elevation – was as much as 40% below the average. “That is exactly what we expect from climate change,” Gleick is quoted as saying. “The snowlike will move up because it is warmer.”

Present conditions: Check out the NRCS’s snow water equivalent map as of January 4, 2018. No, it is not good (unless you live in Montana or Wyoming).

Snowtel sites percent of normal snow water equivalent