Five board members of the Electric Reliability Council of Texas, or ERCOT, which manages most of the electric grid of the state, were expected to step down Wednesday.

The board has come under withering criticism after a freezing winter storm last week that killed dozens and left more than 4.5 million customers without power, some for five days.

The Public Utility Commission of Texas (PUCT), which oversees ERCOT, in a notice late Tuesday said the resignations are by four unaffiliated board members and another board member. Also resigning is a board candidate who withdrew his application.

Gov. Greg Abbott last week had called on the board to resign. He said the independent system operator (ISO) had “failed the people of Texas” during the extended cold snap.

The governor...