INCLINE VILLAGE, Nev. - Picture the Lake Tahoe basin in a deluge of rain. Weeks of downpouring and melting snowpacks. Landslides render highways and roads impassable. No lights, no water, no heat, no food.
Businesses shut down. The local economy is devastated. And little outside help is on the way, considering outside responders are overwhelmed with storm damage in surrounding areas.
A deluge of this magnitude is inevitable in Lake Tahoe's future, but it doesn't have to turn catastrophic - so long as preventative steps are taken now, two U.S. Geological Survey scientists said during a presentation last Thursday at the Tahoe Environmental Research Center.
Such storms will likely come from atmospheric rivers, gargantuan bands of warm water vapor that form over the Pacific Ocean and move eastward, some of which hold enough water to fill the Mississippi River 10 times over, said Dale Cox, a regional hazards coordinator for the federal agency. Satellite imagery shows them to be at least 1,200 miles long and 250 miles wide.
"Atmospheric rivers are particularly vicious storms," added Michael Dettinger, a USGS research scientist. "They lift up mountain ranges more easily than other storms, cool, condense out, then boom - lots of rain."
The weather phenomenon "Pineapple Express" is one example of an atmospheric river, said Cox, adding that the large storms that hit the region and threatened to flood the Truckee River in late November and early December, 2012, were atmospheric river storms.
"You will probably be seeing more atmospheric rivers with climate change," Cox said. "What you can expect from climate change in the west is expanded periods of drought, higher temperatures, sea level rise and more frequent and ferocious storms."
An ARkStorm - a hypothetical term developed by USGS that's short for an AR (atmospheric river) 1000 (k) storm - is an extreme scenario featuring continual downpour of two to eight inches of rain a day for extended periods in California.
The last catastrophic series of rain storms hit California in 1861-62, causing extensive flooding across the state, devastating the economy. According to various historical accounts, newly elected California Gov. Leland Stanford had to be taken to his inauguration in a rowboat.
Cox said current AR 1000 scenario models are scaled back from the 1861-62 storms.
"If people see a possible catastrophic event as being too large, they think it is not believable and they don't prepare for it," he said.
Dettinger said he and Cox came to Tahoe last Thursday and presented at TERC "to discuss who from the area we should connect with so that such an effort was of maximum utility for emergency responders, planners and the community at large."
Michael Schwartz, chief of the North Tahoe Fire Protection District, attended the presentation. He recalled a major storm that hit the Tahoe area in 1986, when roads and highways were closed and there was a high fire danger due to broken gas lines.
"We realize we'll be alone for a while," said Schwartz, in the event an AR 1000 hit Tahoe. "As far as being prepared, we're as ready as you can be."
California communities are starting to use AR 1000 scenario for disaster exercises, Cox said, the most recent of which took place Jan. 23 at Truckee Tahoe Airport, featuring the 95th Civil Support Team out of Hayward, Calif.; Eastern and Central Placer County Hazardous Materials Teams; California Office of Emergency Services; Placer and Nevada County Environmental Health; FBI; Truckee Police Department; and the Las Vegas Metropolitan Police Department's ARMOR Unit.
- Frank Fisher is a freelance reporter for the North Lake Tahoe Bonanza and Sierra Sun. He can be reached for comment at firstname.lastname@example.org.
Learn more about the U.S. Geological Survey at www.usgs.gov
Learn more about atmospheric rivers at www.esrl.noaa.gov/psd/atmrivers