Officials in Northern California said Wednesday they are making "great progress" on repairs to the damaged spillways of the nation's tallest dam before new storms hit the area in the next couple of days.

Bill Croyle, the acting director of the California Department of Water Resources, said the lake behind the Oroville Dam continues to drain rapidly, and has dropped nearly 20 feet since overflowing into an emergency spillway Sunday when it reached full capacity.

"We want to keep that rate of release up as we continue to move out of the reservoir to handle wet weather," Croyle said at a news conference.

A series of storms expected Wednesday and later in the week are expected to be smaller than previous ones that filled the reservoir to capacity, according to Croyle. The damaged main spillway "has been stable for a number of days," Croyle said.

Croyle said crews "are still removing more water from the reservoir than we would receive from the storm system coming in."

National Weather Service forecaster Tom Dang told the Associated Press the first two storms were expected to be light. The first could bring 2-3 inches of rain Wednesday followed by an even smaller accumulation from the second storm.

However, the third storm, starting as early as Monday, could be powerful, according to Dang. "There a potential for several inches," he told the AP. "It will be very wet."

The sheriff of Butte County, Kory Honea, reminded residents that while the risk level was reduced to let people back into the area, "this is still an emergency situation."

Honea said that the nearly 200,000 residents allowed to return home should use the time this week before the next set of storms to fully prepare in case another evaluation is needed.

The initial evacuation Sunday was "chaotic," Honea acknowledged.

"People should start planning where they might go and how they might get there to make things more orderly," he said.

There were a number of homes in the evacuation zone that have been burglarized, but arrests have been made, according to Honea.

The sheriff also called on private drone operators to refrain from flying the devices over the dam, which can interfere with repair work.

Dump trucks and helicopters have dropped thousands of tons of rocks and sandbags over the past couple of days to shore up the dam's spillways, and avoid what officials had warned could be a catastrophic failure and flood downstream.

Croyle said teams were working on plans for permanent repairs to the dam's main spillway that could cost as much as $200 million.

Long-term repairs will likely begin after the spring runoff, when crews can close floodgates for an extended period without the lake refilling with melting snow.

President Trump ordered federal authorities to help California recover from severe January storms — a disaster declaration that also assists state and local officials with the dam crisis.

The Associated Press contributed to this report.