[UPDATE: 2017-02-14 @ 2312: Authorities have now lifted a mandatory evacuation order issued over the weekend to residents who could have been affected by catastrophic flooding from failure of the Oroville Dam emergency spillway. Residents may now return to their homes but have been advised to remain vigilant, should the situation again become critical. The Red Cross shelter in Chico will remain open through a predicted storm.]

Sacramento Valley ARES Section Emergency Coordinator Greg Kruckewitt, KG6SJT, reports that Amateur Radio Emergency Service (ARES®) volunteers are now actively involved in supporting communication for the evacuation and sheltering of nearly 200,000 people living below the damaged Oroville Dam in rural California. The dam, on the Feather River east of Oroville, is the tallest in the US. Following a period of heavy rain, a section of the earthfill-embankment dam’s spillway eroded, and authorities issued an evacuation order for residents living below the dam, in case it should fail. Crews have been attempting to fill the eroded area with rock transported by helicopter.

Butte County ARES EC Dale Anderson, KK6EVX, was called out by the emergency operations center (EOC) on the evening of February 12. Six members of the Butte County ARES team now were deployed a Red Cross evacuation shelter at the Chico fairgrounds. Anderson said shelter managers were discussing the need to establish a radio link with the National Guard. Two VHF radios, one HF radio, and several handhelds were available at the shelter.

On February 12, Yuba/Sutter ARES EC Steve Sweetman, K6TAZ, opened and managed a net to provide information and gather reports of road closures or problems during the evacuation. The net received reports from radio amateurs who were evacuating. Traffic was reported to be very heavy, with a trip that would normally take 20 minutes extending into “3-hour stop-and-go ordeal,” Sweetman said. The net also gathered information on where evacuees could get fuel for their vehicles. “This became a critical need, as the thousands of people evacuated their houses with 1-hour notice,” Kruckewitt said, adding that the net has continued in operation. Sweetman is operating from his house on a high hill outside Yuba City,” Kruckewitt said. “He is safe from flooding and currently has 17 evacuees staying on his property.”

The Sacramento County EC Vince Cracchiolo, KI6NHP, was called into the Sacramento County Emergency Operations Center (EOC) on February 13 as the Red Cross opened a shelter at Cal Expo in Sacramento. Kruckewitt said the Sacramento Valley Section has received offers from hams outside of California offering to help if needed. FEMA reports that 20 shelters are open with 3,680 occupants.

“At this time, we are doing fine,” Kruckewitt told ARRL, although power outages have been reported in Yuba and Sutter counties. “They are identifying the problem,” he said, “so power outages at the Chico shelter are possible.”

“All ARES groups in the Section are on standby, if help is needed. So far, the dam is holding, and repair work is under way at last report.”

According to the California Department of Water Resources (DWR), evacuation orders were issued to residents surrounding Lake Oroville late Sunday afternoon. “DWR has been monitoring conditions at Lake Oroville’s main and auxiliary spillways around the clock for signs of erosion that could threaten the integrity of the emergency spillway and allow large, uncontrolled flows to the Feather River,” the agency says on its website.

“To lower the lake level and thus reduce flows and the potential for erosion at the top of the emergency spillway, DWR increased flows down the main spillway’s damaged, concrete chute to 100,000 cubic feet per second. Current releases remain within the capacity of downstream channels. Oroville Dam is a separate structure from the emergency spillway and remains sound.”