Two Republican senators announced an investigation on Monday into the response to the Palisades fire in Los Angeles, saying the state and local governments, which are led by Democrats, were to blame for the disaster.

Senators Rick Scott of Florida and Ron Johnson of Wisconsin said their investigation would examine why the area’s main reservoir was empty before the fires began and whether preparation for the emergency was sufficient.

At least 31 people died in the wind-driven wildfires that swept through Southern California in early January. Twelve of them died in the Palisades fire, which was centered in the affluent Pacific Palisades community that lies within the Los Angeles city limits, and 19 people died in the Eaton fire, which erupted hours afterward in Altadena, a separate suburb in the foothills of the San Gabriel Mountains to the east.

The congressional investigation could focus on the actions of Gov. Gavin Newsom of California and Mayor Karen Bass of Los Angeles at a critical moment in their political careers. Mr. Newsom is a potential Democratic presidential candidate who is leading a campaign to combat Republican gerrymandering in Texas, while Ms. Bass is running for re-election as mayor next year.

The January fires, which destroyed thousands of structures in Los Angeles and Ventura Counties, have spawned more than a half-dozen investigations, as devastated homeowners and local authorities have sought to pinpoint their causes.

Fire experts have said since January that, in many ways, the catastrophe was almost impossible to fully prepare for. There were hurricane-force winds, supercharged by a rare alignment of powerful atmospheric conditions, driving an inferno through communities that had seen less than a quarter-inch of rain in eight months.