Monthly Archives: April 2018

Snow drought in an average year of precipitation for Truckee River

NRCS 4-24-2018 - Total Precipitation vs. Snow Water Equivalent for water year to date

The Truckee River watershed saw more rain than snow this year. So, this year appears to continue the trend of at least the last decade as rain replaces snow – especially at lower elevations. The maps show just how significant the effect is as we approach the end of the first month of spring. Many sites in the Truckee River basin (including the Tahoe basin) are reporting 101% of the longterm average for precipitation. The picture is different for snow water equivalent, however. Snow water equivalent (the amount of water in the snow pack) is almost or well below the longterm average for this date for sites at lower elevations. You have to go to the highest elevation sites to see average snow water equivalent conditions.

In the graphic below, the blue dots on the left represent sites where total precipitation is 101% and the white sites represent 100% of the long-term average. On the right the 3 sites (between 6400′-7700′) in red have 0% of snow water left; the orange sites have 50% of snow water left compared to the long-term average. Only the site at Big Meadow (8235′) shows 101% of snow water left and one site at Heavenly Valley (8500′) shows 100% of snow water left – both high elevation sites. Click on the graphic to see full size. Or check out the site yourself here.

NRCS 4-24-2018 - Total Precipitation vs. Snow Water Equivalent for water year to date

NRCS 4-24-2018 – Total Precipitation vs. Snow Water Equivalent for water year to date

If the trend continues as expected, there will be very little snow left to melt in the late spring and early summer. When snow disappears earlier, natural stream flow of tributaries and the Truckee River itself decrease. Less natural stream flow often results in additional releases from reservoirs or increased ground water pumping because of our long, dry summers.  Ultimately, it will negatively affect recreation and fish and wildlife that depend on water in the Truckee River.

One Truckee River Month: May 1 through May 31

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.

Truckee River escapes drought designation

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.

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.

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 March 28, 2018.

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