PG&E team responds to “slow moving disaster” of Tulare Lake flooding

Update May 2.

PG&E crews continue to protect equipment and substations from potential flooding in the Tulare Lake Basin. We currently have 125 without power due to flooding.

Divers and electric crews continue to prepare transformers already impacted by the flood for removal by helicopter. Flights with the Chinook heavy-lift helicopter will resume on Tuesday, May 2 and continue for several days. We continue patrols to track water movements and its effect on our equipment.

Work to install a flood barrier around the Angiola Substation is ongoing, with plans to install similar barriers at our Alpaugh and Corcoran facilities in the coming weeks.

Update April 24.

On Sunday (April 23), PG&E flew aerial surveys of the flood basin, and continued our efforts to remove equipment affected by the flooding. In some cases, we are replacing existing infrastructure with new, more resilient equipment designed to handle forecasted conditions in basin area. 

Today we will again fly a Chinook heavy-lift helicopter to remove pad-mounted transformers that are no longer operating due to the rising waters. We will continue removal of other pole-mounted equipment. Work is also ongoing to build flood barriers at the Angiola Substation. 

We ask that residents stay aware of heavy equipment traffic near levies, and to stay clear of hellcopter landing zones for their safety. 

By Denny Boyles

After what felt like a nonstop conveyor belt of winter storms that brought downpours of rain, strong winds and thousands of power outages, most of California is enjoying the return of blue skies.

In the Central Valley communities of Corcoran and Alpaugh, the blue sky is reflected in a mirror no one wants to see – a slowly growing flood as the once-dormant Tulare Lake refills from rivers swelled by a massive snowpack run-off in only the first stages of a spring melt.

The growing flood threatens three PG&E Substations, miles of distribution and transmission lines and dozens of pieces of ground mounted equipment such as transformers.

Local PG&E crews began responding to reports of flooding on March 28. On April 13 PG&E activated Incident Management Team 2 to coordinate efforts to protect infrastructure and keep power on for as many customers as possible. Team 2 Incident Commander Vince Magri said the first goal was to ensure safety and assess the extent of the risks.

“Our first surveys from the ground and air showed what we suspected – waters are already impacting our facilities, and the worst is yet to come. It’s a slow-moving disaster, the water is not coming quickly but we all know it is coming,” Magri said.

To manage the mitigation, Magri’s team have assembled a diverse and unique mix of personnel and equipment. Lineman patrol above the lake in helicopter and on the surface in swamp-style air boats. Dive crews disconnect 5000-pound transformers that are already underwater so that a Chinook helicopter can lift them and carry them to nearby landing sites.

One of the biggest concerns is potential flooding to substations in the towns of Corcoran and Alpaugh, and the nearby community of Angiola. Corcoran has 20,000 residents and is home to state prisons with more than 8,000 inmates.

Adam Kincade, South Valley Substation Maintenance and Construction Superintendent, is overseeing construction of flood mitigation walls around the substations. At Angiola, the walls will be 16-feet high.

“We have to protect against not the just the predicted height of the flood water, but also wind-driven waves that could be more than a foot high,” Kincade said.

Wave action is a concern for Tulare Lake, which was once the largest freshwater body west of the Mississippi River and could grow larger than Lake Tahoe this year.

The lake is fed by multiple rivers carrying melted snow from the southern Sierra Nevada. Those flows that helped Tulare Lake cover more than 690 square miles of land at its largest.

In the last 40 years the lake has only reemerged twice, in 1983 and 1997. In 1983, the snow recorded its highest snowpack ever and it took two years for the lake to fully recede. This year’s snowpack is one of the largest ever with the southern area, which feeds Tulare Lake, at more than 300 percent of average.

“As we plan, we have to consider that some of these communities may be impacted for years. It’s unlike any storm response most of us have seen during our careers. The blue skies don’t mean the problems are over,” Vince said.