Lake Tahoe may be the largest alpine Lake in North America but temperatures here are rising. Increasing temperatures the year-round are seen for both the air and the water according to a report by University of California, Davis “Tahoe: State of the Lake 2018“. The long-term average daily minimum temperature in the Tahoe Basin rose 4.4ºF over the past 100 years while the average daily maximum temperature rose 2.2ºF. The number of freezing days – that is, the number of days where the temperature remains below 32ºF – has decreased by 30 days in that time. And the annual average water temperature of the Lake – while a more complicated statistic – shows the Lake warming 1.1ºF since 1970, “… bringing it to the warmest value recorded…” – 43.3ºF. The July 2017 surface water temperature of the Lake was the warmest ever recorded at 68.4ºF.

The Sierra Nevada Mountains on the west shore of Lake Tahoe veiled by smoky skies from wildfires.

The report says that in 2017 “…the monthly air temperatures were higher than the 1910-2017 average…” in 11 out of 12 months. And rising temperatures have implications for the health of the forest as well as the clarity of the Lake’s fabled waters. If CO2 continues to rise, temperatures in the Tahoe Basin could be 7 to 9ºF higher which will increase the “climate water deficit” – with likely negative effects on the entire ecosystem of the forest and lake environment. The report says that such an occurrence is the “subject of ongoing research.”

Truckee Meadows warms up to HOT

For those of us who spent July in Reno, it is no surprise that it was the hottest month ever in Reno exceeding last year’s “hottest ever July” by 1.3ºF. As a Renoite of nearly 7 decades, it is shocking that this July saw average temperatures 6.9 degrees above the 1981-2010 average. The cool summer evenings of the Truckee Meadows are a distant memory with the July 31st tie of the highest low temperature for Reno of 77ºF  . The month was 6.9 degrees above the 1981-2010 average.

NOAA Temperature for Reno July 31, 2018 (click)

So just how hot was July 2018 here in Reno?

We had the highest average temperatures of 81.8ºF – a staggering 6.9ºF above the 30 year running average. It set a record for the most days at or over 100ºF – 14.  The high temperature for the 31 days of July 2018 never was below 90ºF – matching the hotness of July … wait for it … 2017!

We often hear about “normal” temperatures when the weatherwoman on TV or Radio talks about being above or below the normal temperature. It is actually defined as the 30 year average calculated every decade. The current “normal” comes from the period 1981 to 2010. In 2021, normal temperatures will be calculated during the period 1991-2020. So all these new hot  temperatures will be part of the “average” and “normal”. In this way, the rising temperatures get smoothed out and don’t seem as out-of-bounds as they would if we used, say, a 50 year average or a 75 year average. Reno’s records date back 125 years, but worldwide, many temperature records are far longer.

… And the warming temperatures are caused by?

Climate change, or global warming, is the result of the the physics of carbon dioxide (CO2) released into the upper atmosphere by burning carbon-based fuels – coal and oil and gas. The knowledge of this physics isn’t new; its been known by scientists since the 19th century who said then that it would warm up the earth. Presently, if you search on the internet for “climate change”, you’ll find far more nonsense about a “hoax” than you’ll find actual scientific information which is verified by scientists – who know a thing-or-two – and our own experiences with each passing year.

Just where does the Truckee River’s Water Go? Check back for an update on Truckee River water  – diversions, dams, and development takes a bite!

Hunter Creek cascades into the Truckee River at Mayberry Bridge near Mayberry Park in Reno in June.

The Truckee Meadows Parks Foundation is developing a new program and has sent out the following job description for a Wetland Restoration Program Director:

“Truckee Meadows Parks Foundation supports Reno, Sparks, and Washoe County parks primarily by providing in-park programming, fundraising for park infrastructure upgrades, and opportunities for citizen engagement. The Parks Foundation is an independent, 501 (c) (3), nonprofit organization. In the five years since its founding,  the Parks Foundation has grown to a full-time permanent staff of five individuals overseeing 15 AmeriCorps members who serve one-year terms. Our current programs focus on improving community health and wellness, science education, and developing appreciation for the natural and cultural history found in our local parks. … For questions, call 775-410-1702 or visit www.tmparksfoundation.org for more information.”

One Truckee River kicks off its inaugural OTR Month with river events for each day this May. Activities include river tours, yoga on the river, learning about the river, river and park clean-ups, vendors offering food and more. Below is a schedule of some of the events. The One Truckee River website (onetruckeeriver.org) will have the details so be sure to visit to plan how to join in.

Southern California, Arizona, Utah, Colorado, and New Mexico are experiencing severe drought conditions, but far western Nevada and parts of northern California are not. In fact, the map on the US Drought Monitor website currently shows that the Truckee River and Lake Tahoe basins are in the “none” category. We are however, surrounded by “abnormally dry”. Perhaps it would be safer to say we are on the cusp of drought conditions later this year. Dry conditions usually persist here from late spring into early fall. Being dry for half of the year is the norm for western Nevada – actually, most of the far western states. Nevada has the distinction of having the lowest average annual precipitation statewide – less than 10″. Much of western Nevada is even lower at 7.4″ or less average annual precipitation.

Drought Map for 3-29-2018 – On the edge of the drought the map appears to exclude the Truckee River and Tahoe Basins – at least for now.

Truckee River in Reno with flows at 2,000 CFS during the last weekend in March 2018.

For the moment, however, we can enjoy the high flows in both the Truckee River – currently above 2,500 cubic-feet-per-second (CFS). The snowpack is already melting and won’t provide runoff for anywhere near as long as we saw last year. A storm is forecast for the end of the week.

As we mentioned in our earlier post, the Federal Water Master is releasing water from Lake Tahoe today at more than 1,300 CFS (and rising as this as I write this). Lake Tahoe stands just below 6,228.6 feet in elevation. Pyramid Lake may actually be rising due to increased inflows and may now be higher than the last official reading reported at 3,802.37 feet surface elevation on February 28, 2018.

Snow is melting fast on the north-facing slopes of the Carson Range shown here at about 6,400 feet.

Most low elevation areas – below 7,000 ft – are already snow free such as here on the Jones-White’s Creek Trail.

The Carson River is currently flowing at nearly 1,000 CFS (April 2, 2018). Diversions from the Carson River for agriculture have already begun. Diversions to agriculture place a huge burden on the Carson River and cause it to be dry by early summer most years before it gets to Lahontan Reservoir. When flows are low on the Carson River and Lahontan Reservoir has storage available, then the Truckee-Carson Irrigation District (TCID) diverts water from the Truckee River (it uses the entire flow of the Carson River that is available). Diverted Truckee River water flows through the “Truckee Canal” and dumped out at Lahontan Reservoir just upstream of the Dam. Water diverted by TCID never gets to Pyramid Lake; the loss of water caused Pyramid to fall 80 feet in elevation since diversions began 113 years ago.

Carson River at Mexican Dam at Silver Saddle Park in Carson City,  March 28, 2018.