Rising Temps to Accelerate Runoff
Rising Temps to Accelerate Runoff
Conditions Pose Hazards in and out of the Water
Rising temperatures between now and July 4 are expected to accelerate snowmelt in the Sierra, bringing peak water flows to local creeks, rivers, and other channels as well as increased dangers for the public.
Runoff from the historic Southern Sierra snowpack – which was approximately 300 percent of normal on April 1 – has been slowed somewhat by unseasonably cooler temperatures earlier this spring and summer. Agencies including Inyo County, the Los Angeles Department of Water and Power, Southern California Edison, and Caltrans warned for weeks that the reprieve would not last and, according to the National Weather Service, it will indeed come to an end with the arrival of temperatures in the 90s and above next week.
Snow levels in the Sierra are still extraordinarily high, even by 2017 standards, and higher temperatures are expected to open the floodgates, with water levels rising and flow rates increasing throughout the region. One million acre-feet (one acre of land covered in one foot of water), or 326 billion gallons of water, is expected to come down from the High Sierra through at least July.
Residents and visitors are strongly encouraged to obey all road closures and avoid areas with swift water – for their safety as well as that of first responders. Many local waterways are raging with extremely frigid whitewater flows and several of those have already broken their banks, including the Owens River, Bishop Bypass, and Independence Creek. The latter is a particular area of concern due to the amount of snow feeding the channel. As such, the evacuation warning issued Monday afternoon for the Seven Pines area off Onion Valley Road will remain in place for the foreseeable future.
Inyo County Sheriff’s personnel were summoned to the area Sunday by the Independence Volunteer Fire Department and one residence was evacuated at that time. Continued, extreme levels of runoff in Independence Creek prompted the Sheriff’s Office to issue a Code RED alert Monday afternoon due to the potential threat to life and property. With the potential for waters to rise overnight, individuals who need extra time to evacuate or anyone with large animals was urged to pack up and leave at that time. Inyo National Forest personnel were expected to reach out to all Seven Pines residents to help coordinate evacuation.
An Inyo National Forest hydrologist conducted an assessment on Tuesday, determining that flows in Independence Creek had peaked at 158 cubic-feet-per-second (cfs) at 1 a.m. Monday – a flow rate equivalent to almost 91,000 gallons per minute. This is in steep contrast to last year, when the flow rate in Independence was so low, none of its water made it to the L.A. Aqueduct. The Lower Owens River is expected to convey flows in excess of 800 cfs (approximately 300,000 gallons per minute) this week. For perspective, the highest amount of cfs the southernmost section of the river sees in a normal year is approximately 600 – for a very short time during annual flushing flows. In its upper reaches, the Owens River is flowing at a staggering 1,400- 1,500 cfs – just outpacing LADWP’s efforts to spread the water at a rate of 1,300 cfs.
Most roads crossing the river are expected to flood.
Multiple areas of the river have been experiencing out-of-bank flooding since May, including water flowing onto Owens River Road. Resulting road damage led LADWP to close sections of Owens River Road between Warm Springs and Collins roads, and between Warm Springs Road and Line Street. LADWP closed access to the river earlier this year between East Line Street and Warm Springs Road, isolating the popular swimming hole known as “The Ropes and High Banks,” due to severely undercut and eroding banks.
The public is strongly encouraged to avoid waterways this summer with the exception of Diaz Lake, Millpond, Buckley Ponds, and Klondike Lake. Swift-water dangers include water cold enough to induce hypothermia, hidden underwater snags, and heavy debris.
Following are additional flood- and runoff-related closures in Inyo County, including roads closed as part of Forest Closure Order issued by the Inyo National Forest:
Chalk Bluff Road
Brockman Lane
Manzanar Reward Road
Lone Pine Narrow Gauge Road
Cottonwood Road
Mesquite Valley Road
Onion Valley Road
Silver Canyon Road at forest boundary
Wyman Canyon Road at forest boundary
Coyote Flat/Valley Road from Bishop
Coyote Flat/Valley from Big Pine
Roads west of Warren Bench (accessible from Sugarloaf or Glacier Lodge roads)
Buttermilk Loop at Horton Lakes Trailhead and at State Route 168
White Mountain Road just past Shulman Grove Visitor Center
State Route 136
The Inyo National Forest reported the Closure Order will be lifted as soon as road conditions allow for safe travel. Caltrans does not have an estimated reopening date for S.R. 136, which is closed due to flooding between U.S. 395 and Dolomite Loop Road and the concern that continuous water flow is potentially undercutting the highway. State Route 190 out of Olancha is the alternate route for drivers trying to reach the town of Keeler or Death Valley National Park.
For more information, including where to obtain sandbags for your home or business, visit:
https://www.facebook.com/InyoCountySheriffsOffice
https://ladwpeasternsierra.com/runoff2023
https://inciweb.wildfire.gov/incident-information/cainf-inyo-national-forestflood-response
https://wsoweb.ladwp.com/Aqueduct/realtime/lvrealtime.htm
https://www.weather.gov/safety/coldwater
