Category Archives: Keep it flowing

Cities, towns, development, farms, ranches take water from the Truckee River – some years taking nearly its entire flow

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

 

 

 

 

Are dry conditions going to continue?

Fall color, Wingfield Park in downtown Reno

Last year December saw rising water levels at Lake Tahoe. The first 12 days of December are seeing a falling lake level. Weather-wise, the next 10 days appear to be dominated by high pressure which pushes all the storms away from the west coast. Fortunately, we don’t have to deal with the fires that are affecting the Southern California communities, but the dry weather is worrisome as a portent of a return to drought conditions that have dominated the 21st century for the west coast and especially, Nevada and California. Truckee River flows are still running high due to release of water from Lake Tahoe and storage reservoirs. This is likely to allow sufficient storage in reservoirs and Lake Tahoe in case winter turns “wet”.  Lake Tahoe’s elevation is still considerably above its 21st century average water elevation.

Satellite images, such as this recent one from this eventing, show the large high pressure area that is directing storms away from  the Pacific Coast of California.

High Pressure dominates western USA.

The 2017 rise of Lake Tahoe is very impressive from the storms in January and February 2017. The current situation is that Lake Tahoe will decline unless we receive winter storms that raise the level of the Lake directly and build a snow pack.

Lake Tahoe elevation over the last 12 months (USGS).

Most of winter is still to come, but a dry December is not a great way to begin the “wet” season.

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.

 

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Winter storm forecast for late Friday into weekend

A warm October ended with balmy days and a calm evening for the trick-or-treaters on our street. The summer-like weather that dominated October here in Reno and western Nevada may be coming to an end this Friday.

Forecast for the 5 day period beginning Nov 1, 2017. Click for full size.

Forecast for the 5 day period beginning Nov 1, 2017. Click for full size.

The National Weather Service is forecasting a storm moving into the region late Friday continuing into the weekend. The forecast calls for 50 mph winds and precipitation in the valleys east of the mountains, but for only small amounts of rain with a possibility for snow toward the end of the storm. The Sierra and Carson Range, however, may do better with moderate rain and snow called for late Friday, Saturday and Sunday.

Mid-October saw a cold front that brought around a quarter inch of precipitation at my house in northwest Reno. Most of the snow that fell in the mountains has melted. Travelers across the middle of Nevada report there is no visible snow on the mountains.

The National Weather Service Climate Prediction Center says that this is a “la niña” year and the long range forecast – November through January – calls for California and Nevada to have an “equal chance” for a wetter or dryer than average early winter season. We can always hope that it is the former not the latter.

Not surprisingly, the NWSCPC is calling for a warmer than average early winter in California and Nevada – in fact, most of the US outside of Alaska and Hawaii. Click on the maps below to see them full sized or visit the link above and check out all the forecasts.

 

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