Category Archives: Drought

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

 

 

 

 

Truckee River Winter Forecast: Temps up; coin-toss for wetter or drier

NOAA precipitation forecast probabilities for Dec 17-Feb 18

NOAA precipitation forecast probabilities for Dec 17-Feb 18 (click for full size)

The next 3 months, the typical winter here in western Nevada and the Truckee River basin, will determine whether we’ll see a wetter than normal water year – or drier. The forecast? Precipitation this winter currently is a toss-of-the-coin or equal chances for a wet or dry year. Just a little to our south the chances for a dry year increase; to our north the chances for a wet year increase. This forecast looks into our 90 day future from the middle of November 2017.

Whether precipitation prognostications are accurate, we’ll know on February 28, 2018! Western Nevada did get a significant rain last week with some locations in Reno reporting more than an inch of rain. (At our house we had 1.25″!) The Carson Range and the Sierra Nevada received considerably more – especially on the west side of Lake Tahoe. The Lake rose more than 3.5 inches to 6,228.1 ft. Currently, an “atmospheric river” is hitting the Oregon and Washington coast, but missing the Sierra completely. Hopefully, we’ll see storms similar to our recent dump of rain and snow coming soon. The health of the Truckee River, Tahoe, and Pyramid depend on it.

Pyramid Lake at Popcorn Rock Beach, August 2017.

Pyramid Lake at Popcorn Rock Beach, August 2017.

Over the 2-day rain event that started in the late evening of November 15, flows jumped 5-fold in the Truckee River through Reno. Truckee River flows peaked at 3,000 CFS (cubic-feet-per-second) at Pyramid Lake by November 17. As I write, flows of the Truckee through Reno are still more than 1,000 CFS and releases from Lake Tahoe dam into the Truckee River have been increased by the Federal Water Master to more than 1,000 CFS. Flows this winter in the Truckee River will be determined by the amount of precipitation we receive since currently Lake Tahoe and other reservoirs on the Truckee River are nearly full. Lake Tahoe stands today at 85% full, (last year it was essentially empty!) and the next largest reservoir in the Truckee River watershed, Stampede, stands at 90% full. A wetter than average winter means the Truckee River will see benefits for trees, plants, fish and wildlife along its entire length and Pyramid Lake will continue to rise making up for serious declines in water surface elevation suffered during the first 16 years of the century.

NOAA temperature forecast probabilities for Dec 17-Feb 18 (click for full size)

The NOAA 3 month forecast for temperature puts most of California (including all of the Sierra) and nearly all of Nevada likely to be warmer than average. It is no surprise since we’ve seen the consistently warmest temperatures in western Nevada and the Sierra during the past 2 decades. Without serious action on the climate change front, that is very unlikely to reverse itself anytime soon.

 

Related articles across the web

Changing Climate or Wet Year?

If the fish and wildlife dependent on the Truckee River and Pyramid Lake and Lake Tahoe could cheer, we’d certainly be hearing the shout-out because of this winter’s huge rain and snow events bringing near record river flows this spring. After such a long drought and long-term rain and snow deficit beginning in 2000, this year has been a celebrated event.

Is it just a wet year following a drought or are erratic swings in precipitation to be expected from Climate Change? Are having the driest year on record in 2014-15 and the wettest year on record in 2016-17 the pattern of a new “normal” for the western US?

Truckee River at Mayberry Park viewed from Steamboat Ditch Trail

This is a winter and spring of superlatives for Truckee River flows. Pyramid Lake has risen, so far, 9.1 feet since January 1, 2017 and on June 1 was at a water surface elevation 3,801.24 feet above sea-level. This is a tremendous benefit to the endangered cui-ui fish found only in Pyramid Lake as well as its huge Lahontan Cutthroat Trout that wow fishermen at 15 or even 20 pounds. In the last 20 years, the high water elevation measured at Pyramid Lake was 3,817.6 feet on August 17, 1999. Prior to the federal government’s 1905 Newlands irrigation project that diverted water to expand farmland in Lahontan Valley, Pyramid Lake was relatively stable at an elevation of about 3,875 feet.†

The Truckee River on June 8, 2017 flowed at 3,900 cubic-feet-per-second (CFS) or 5 times the long-term average flow on that date – higher flows only occurred once before in 1983 (which was a wet year preceeded by several wet years).

Lake Tahoe has gone from below its rim last October to rise more than 6 feet totalling 736,000 acre-feet of water with more still coming. On June 19, the water surface elevation of Lake Tahoe was just 4.8 inches below its legal maximum of 6,229.1 feet elevation. The result of the rainfall events and exceptional snowpack runoff has contributed to the large flows of the Truckee River from late winter into spring. Summer flows in the Truckee River will also be larger than seen in many years.

Another wet year could bring Pyramid Lake back to levels not seen since 1999 when Pyramid Lake’s water surface elevation was 16 feet higher than today. Flows in the Truckee River are typically higher in multiple wet years in a row when reservoirs are already full and water must be released from reservoirs like Lake Tahoe rather than stored. If the Sierra around Tahoe has a similar rain and snow-filled winter season for 2017-18, then all of the runoff would flow to Pyramid Lake resulting in a significant inflow increase to Pyramid and raising the water level of Pyramid Lake substantially more than we saw this year. But, if next winter is average or dry, then runoff to Pyramid will be substantially less and no bump in Pyramid’s water level will occur.

American White Pelicans hang out at the Truckee River delta at Pyramid Lake April 2017.

American White Pelicans hang out at the Truckee River delta at Pyramid Lake April 2017.

So, with wild swings in preciptation observed since 1997, what can we expect from the winter of 2017-18? How will climate change – read climate warming especially in the northern hemisphere – affect snowfall and rainfall that keeps the Truckee River flowing and water in our Lakes?

With President Trump’s withdrawal from the International Climate accord, it appears that, at least from the Federal Government, it is a reversal of positive action to protect the earth from the most disastrous effects of a warming world caused by burning fossil fuels. The new administration seems determined to rapidly increase use of fossil fuels and stop solar and wind and geothermal technologies from competing.

Click to see.

Each of us and individual states and businesses can, however, choose to reject returning to the coal-style economy of the last century which brings higher temperatures, increased evaporation and evapotranspiration, and is very likely part of the wild swings in weather world-wide, and especially concerning for the arid western US.

Meanwhile, NOAA reports that there is a 50-55% chance that there will be “neutral” conditions in the Pacific meaning no “el niño” or “la niña” is being forecast at this time. What does that mean for the upcoming winter weather? We’ll find out at the end of March 2018.

Expect the wild ride to continue.

† Under natural conditions and prior to the 1905 Newlands irrigation project, Pyramid Lake and Winnemucca Lake both received water from the Truckee River. When Pyramid Lake reached an elevation of around 3,880 feet, water would flow through a channel north of Chalk Bluff to Winnemucca Lake. Because of the Newlands irrigation project, Pyramid Lake steadily dropped and no water could flow to Winnemucca Lake. Winnemucca Lake, once a National Wildlife Refuge, dried up in 1940. Pyramid Lake is presently about 80 feet lower in elevation than its historic level. The channel to Winnemucca Lake is still visible from highway 447 as you go around Chalk Bluff. The Pyramid Lake people in the 1920s recorded the precipitous fall of Pyramid Lake by recording elevations on the famous Pyramid. The dates inscribed on the Pyramid show how quickly it shrank as diversions began. The dates of 1924, 25, 26, 27, and 28 are visible even today each showing the successive decline in the Lake’s elevation.

Pyramid Lake dates inscribed on Pyramid

Anticipating winter snows for Truckee River flows

Despite the rains of October in the central Sierra, Tahoe today is still 3.6″ below its rim and no water flows to the Truckee River from the Lake.  Most of the Truckee River flow comes from tributaries downstream of Lake Tahoe’s outlet including the Little Truckee River, its largest tributary. It is, however, likely that Tahoe will rise above its rim in the coming weeks as winter weather approaches. Filling Lake Tahoe to its maximum elevation would raise the current level more than 6 feet and require at least a 200 percent water year or double the long-term average annual precipitation of snow and rain.

Lake Tahoe elevation week ending 12-05-2016

Lake Tahoe elevation week ending 12-05-2016

October was a wet month in Reno with two storms that each produced over an inch of rain. It was extremely welcome after a long and very dry summer and early autumn. The storms resulted in record October rainfall for some places in the central Sierra and Lake Tahoe. Temperatures remained warmer than “normal”, however, until late November when it finally cooled off. Mt Rose Ski area on the Mt Rose Highway is reporting 13″ of snow at the lodge of natural and artificial snow and 25″ at the 9,800 foot level as I write this. Squaw Valley-Alpine Meadows Ski Resort in California reports a base of 28″ and anticipates up to 2 feet of snow from a series of storms predicted to arrive Wednesday a stay into Saturday. News of the wet October have made a hoped for wet winter in the central Sierra after last year’s dismal “El Niño” palpable. [Find an SFGATE report on the October rainfall/snowfall here.]

Nov 16-Feb 17-precipitation-outlook

Nov 16-Feb 17-precipitation-outlook

NOAA forecasts Northern California and Nevada will see a 50-50 chance of average precipitation under the “La Niña” conditions in the central Pacific Ocean. However, southern California and Nevada as well as most of the southwest and southeast US are forecast to see dry conditions during the “La Niña” winter. Some are saying that there is a good chance for more snow this year around Lake Tahoe northward to the Cascades.

US Drought Monitor Map 2016 11 29

US Drought Monitor Map 2016 11 29

The US Drought Monitor is still showing Reno in the Moderate to Severe drought category despite the recent rains, but soil moisture conditions have improved as you go north toward Oregon. California mostly remains in drought with a large portion of central and southern California in the most severe drought categories. Drought conditions in Nevada have moderated with western and southern Nevada remaining in the drought categories (click map for full size).

Truckee River flow through Reno is running around 200 cubic-feet-per-second (CFS).  Most of the water in the river, however, is not making it to Pyramid Lake, captured instead at Derby Dam and sent to Lahontan Reservoir through a canal.

Unfortunately, Pyramid Lake’s elevation continues to fall due significantly to the diversion of Truckee River water into the canal built by the Bureau of Reclamation in 1905 as its very first project. Water is taken out of the Truckee and sent through an unlined canal from Derby diversion dam on the Truckee all the way to Lahontan Dam on the Carson River. Since the beginning of the drought in 2000, Pyramid Lake has fallen approximately 27 feet in elevation exposing large land areas previously covered by water including shrinking the Lake on its south end to puddles near the mouth of the river. Most of the loss of water to Pyramid Lake is due to diversions to the Newlands Project, however, rather than the drought itself. (More on this later)

Derby Dam on the Truckee River diverts Truckee River water to the Carson River for the Newlands Irrigation Project starting in 1905.

Derby Dam on the Truckee River diverts Truckee River water to the Carson River for the Newlands Irrigation Project starting in 1905.

The Truckee Canal diversions have resulted in the loss of Winnemucca Lake in the valley adjacent to Pyramid Lake and the approximately 80 foot drop in elevation of Pyramid Lake itself since the early 1900s. This amounts to an approximately 8 million acre-foot water deficit for Pyramid Lake, the largest body of water entirely within Nevada or, in other words, represents nearly two decades worth of the average flow of the Truckee River that Pyramid Lake never received.

Pyramid Lake benefits from high precipitation years because of reduced diversions from the river when flows are high. During the drought starting in 2000 there have only been two periods of significant flows to Pyramid Lake which raised its level over the previous year. (click to see photo comparison at full size)

Pyramid at Pyramid Lake changes over recent decade and a half are dramatic

Pyramid at Pyramid Lake changes over recent decade and a half are dramatic

Will this year produce snow and rain that will finally raise Pyramid Lake’s level again and restore the flows to the Truckee River?

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Click the either of the images below to see them full size.