Author Archives: Dennis Ghiglieri

About Dennis Ghiglieri

My concern for the Truckee River grew over the years. It started with picking up trash and supporting better water quality. I helped create the "living river"plan with other citizens on the Community Flood Coalition; a plan to reduce flood impacts to infrastructure through river restoration and protection of the floodplain. I understand how critical the Truckee River is to the environment – and economy – of our entire region. I'm hoping that through these pages we can all understand our connection to the Truckee River and why we need to protect it.

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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Jul-Sept 2017 Temps up (way up)

How hot was it? Pretty hot.

The National Weather Service reports that Reno, NV – yup, right here in river city – set a new record for a 51 day stretch of 90 degree or higher temperatures shattering the previous record from just 7 years ago of a 35 day streak.

Overall, the summer had the highest average temperatures ever recorded for the area, too, 77.2 degrees – nearly 5 degrees above the long-term average. And, Reno sweated through a record 16 days of 100 degree or higher temperatures this summer.

Warm daytime temperatures are often taken in stride by most of us. Temperatures throughout the west and especially in Reno have been rising steadily for many years.  The RGJ noted that overall average temperatures have been steadily warming for the past 70 years.  The average minimum temperature increase means many more days of the year have temperatures above a killing frost resulting in a long growing season more often than in the past. These warmer temperatures impact the urban environment when people need to water earlier in the spring and later into the fall due to both warmer temperatures and the length of time with above freezing temperatures.

This summer California and Nevada during July-September showed a strong warming in both the maximum and minimum average daily temperatures. It isn’t much of a surprise to most of us, but the consequences are more need for irrigation outdoors.  The Truckee Meadows Water Authority (TMWA) spokesman said at a “Water Smart” forum last week, that the water purveyor hadn’t noticed any increase in water use due to a longer irrigation season in a response to a direct question. TMWA does not have information on water use per capita or by type on its website when reviewed for this article.

Check out the graphics on average minimum and maximum temperatures for Jul-Sept 2017 for the USA and the overall average temperatures (last graphic).

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Truckee flows cut while Tahoe nearing maximum storage behind dam

The latest flows from Tahoe (as of 7/13/17) are a mere trickle compared to the flows of the previous 5 months. Flows over the past 4 days from the Tahoe Dam have dropped each day from 300 CFS on July 10th, 200 CFS on July 11, 170 CFS on July 13, and now 70 CFS on July 14. Lake Tahoe’s water surface elevation has not risen over the past week and stands currently 1.3 inches below its legal maximum of 6,229.1 feet. Does the cut in releases into the Truckee mean the Water Master must store that last 1.3 inches of runoff behind the Tahoe Dam?

The reservoirs on the Truckee River are all now essentially full. While there is still snow in the higher elevations, the low elevation snow pack is now gone reducing the amount of runoff in creeks and streams flowing into the Truckee and Tahoe. Current storage stands as follows:

Reservoir on Truckee River

Storage July 14, 2017 acre-feet

Capacity acre-feet

Percent Full

Lake Tahoe (Water Surface Elevation in feet AMSL)

6,228.99

6,229.10

99.9982%

Donner Lake

9,555

9,500

100.5789%

Independence Lake (owned by Truckee Meadows Water Authority)

17,588

17,300

101.6647%

Prosser Reservoir

24,499

29,840

82.1012%

Stampede Reservoir

226,394

226,500

99.9532%

Boca Reservoir

40,761

41,110

99.1511%

Note: Martis Reservoir on Martis Creek, a tributary to the Truckee River, is used for flood control and currently holds 890 acre-feet due to leakage
Reservoir on Carson River Storage July 14, 2017 Acre-feet Capacity Acre-feet Percent Full

Lahontan Reservoir

305,038

295,542

103.2131%

Lahontan Reservoir stores water diverted from the Truckee River by the Truckee-Carson Irrigation District via the Truckee Canal and the Carson River for the Newlands Project. Since mid-January diversions have been limited due to high flows on the Carson River with current diversions going to irrigation in the Fernley area and the Fallon “bench” lands portion of the Project but not to Lahontan Reservoir.