Nebraska's largest city struggled Saturday to restore power to thousands of residents a day after a severe storm damaged homes, uprooted trees and killed two people in a neighboring community.

It could take a week to fully restore electricity after high winds from Friday's storm, officials said. The storm is one of the worst the Omaha Public Power District has dealt with, said CEO Gary Gates.

Nearly 50,000 customers remained without power Saturday afternoon, utility spokesman Jeff Hanson said. At the peak of the failures, 126,000 customers lacked electricity.

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"We've made very good progress so far with our restoration efforts, but as the work proceeds we're going to see fewer repairs that restore power to large numbers of customers," Gates said.

Some customers might not have power restored until next Saturday, Gates said.

The storm ripped off some roofs and damaged others, shattered windows, and toppled trees. Several homes will be declared unlivable, but city and county officials did not know how many.

High winds predicted for Saturday never materialized, alleviating fears of further damage and disrupted recovery. A dry weekend forecast was expected to help the cleanup effort.

The city released untreated sewage into the Missouri River for several hours until a generator restored operations early Saturday, public works director Bob Stubbe said. People were warned not to wade or swim in the river at Omaha or for miles downstream.

Friday's storm killed two people in Council Bluffs, Iowa, across the river from Omaha. A tree fell on the car they were in, also injuring a teenage girl.

In Illinois, strong winds knocked down tents at an art fair, leaving about 10 people injured in the north Chicago suburb of Evanston, fire officials said. Utility crews had restored power to 45,000 customers and were working to restore about 17,000 more, officials said.

The storm also interrupted practice for the U.S. Olympic swimming trials at Omaha's Qwest Center.

Swimmers returned early Saturday for the first of two practice sessions. The eight-day meet to decide the U.S. Olympic team begins Sunday, with 1,250 swimmers competing.

Much of the debris outside the arena had been cleaned up Saturday, but the building's electrical system was still being assessed, officials said. Damaged ceiling panels were being replaced.