Lake Tahoe Warming; Truckee Meadows sees hottest July

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 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

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.

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

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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.