California & Nevada Drought map has changed

The storms that have hit northern California and Nevada during the last 6 weeks have changed the drought map dramatically from earlier in the winter. Rain in northern California has filled reservoirs and sent rivers flooding for the first time since 2005 in several areas in both northern California and Nevada – including the Truckee River here in Reno and Sparks.

Hunter Creek flooding into the Truckee River at Mayberry foot bridge.

The Reno Gazette-Journal reported today that the drought in northern California is officially over. The categories “severe”, “extreme”, and “exceptional” drought, however, persist in southern California according to the US Drought Monitor. Parts of western Nevada still have persistent drought but in the lower drought categories of “Abnormally Dry” and “Moderate”.  Storms categorized as “Atmospheric rivers” that bring sub-tropical moisture to the west coast appear responsible for the intense rain storms that have changed the outlook in northern California and Nevada.

Drought Monitor Map as of 1-13-2017 (drought_monitor-20170110_west_trd)

While the picture can change again at a moments notice, there is still a chance that additional storms will keep the region ahead in precipitation for the entire water year and bring a partial respite from the effect of a persistent drought pattern that began in 2000. [The water year runs from October 1 to September 30.]

On December 1, 2016 Lake Tahoe was below its rim by 3″ even after a wetter than average October. No water had flowed to the Truckee River from Lake Tahoe since September 13th. Today, Lake Tahoe has risen to 8″ above its rim with the Truckee River flowing at 26 CFS (cubic feet per second). Natural outflow from the Lake could be greater than 26 CFS since the Lake Tahoe dam at the outlet of Lake Tahoe controls the flow of the river according to the Truckee River Operating Agreement. Flows from the two rainstorms that pushed the Truckee River above flood stage in Reno and Sparks and all the way to Pyramid Lake will have a substantial benefit to the overall health of the river. The long warning period (at least 4 days ahead of the event) that residents and businesses received were responsible for minimizing the damage to buildings and homes.

Truckee River at Rock Park in Sparks (flow is around 1,100 CFS)

Truckee River at Rock Park in Sparks (flow is around 1,100 CFS)

Comparing December 1, 2016 to January 13, 2017 for a few sites at Lake Tahoe shows just how quickly a few storms have changed the picture at this point in the winter.

Location

12/01/16

01/13/17

Lake Tahoe water surface elevation

6222.74

6223.66

0.92 ft rise

Truckee River Flow at Reno (changes daily)

247 CFS

1,590 CFS

Truckee River Flow at Tracy (changes daily)

296 CFS

2,420 CFS

Truckee River Flow at Pyramid Lake (changes daily)

112 CFS

3,350 CFS

Ward Creek SNOTEL site (848) at 6745 ft: Snow water equivalent in snowpack

4.5 inches

136%

25.5 inches

189%

Ward Creek SNOTEL site (848) at 6745 ft: Snowpack depth

24 inches

93 inches

Ward Creek SNOTEL site (848) at 6745 ft: Total precipitation

25.8inches

194%

72.4

243%

Mt Rose Ski Area at 8801 ft: Snow water equivalent in snowpack

4.2 inches

81%

40.4 inches

246%

Mt Rose Ski Area at 8801 ft: Snowpack depth

22 inches

153 inches

Mt Rose Ski Area at 8801 ft: Total precipitation

17.6 inches

193%

49.3 inches

219%

Truckee River outlet at Lake Tahoe below its rim in fall of 2015 - 2015-02-16

Truckee River outlet with Lake Tahoe below its rim in 2015-02-16

Lake Tahoe Dam at the outlet to the Truckee River February 2015

Lake Tahoe Dam at the outlet to the Truckee River February 2015

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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.

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