Temperatures rose to above-freezing in Missouri and Illinois Tuesday as thousands of residents remained without power after a major blackout caused by the first snowstorm of the winter season.

The number of deaths blamed on the storm that hit Thursday rose Monday to at least 23, with three more deaths reported in Missouri and one more in Illinois. The causes included weather-related traffic accidents, fires, carbon monoxide poisoning and exposure, officials said.

The St. Louis-based utility Ameren Corp. reported almost 190,000 homes and businesses still without power Tuesday in Illinois and Missouri.

The utility said it would be several more days before power is fully restored to the region.

"We've had some ice storms before. This one puts them to shame," said Ron Zdellar, vice president of energy for AmerenUE, who has worked for the company for 35 years.

Utility crews were working 18-hour shifts, especially in the biggest problem areas, where ice coated roads and utility poles. Workers from 14 states were helping.

The storm also caused widespread power outages elsewhere as it blew snow and ice from Texas to Michigan last week and battered parts of the Northeast with thunderstorms and high winds.

The combination of low temperatures, downed power lines, ice-covered poles and brittle tree limbs hampered repair efforts.

"We knew when this thing hit, it would be far different from anything we've seen before," Zdellar said.

Some people slept in shelters during their search for warm surroundings. The Missouri National Guard was sent to the St. Louis area after the storm to make sure people were surviving without electric light and heat.

The same was happening in neighboring Illinois, where Gov. Rod Blagojevich ordered National Guard troops to begin checking on Decatur-area residents.

After spending three days at a shelter in a converted recreation center, Angela Luster hitched a ride with the National Guard to check on her apartment.

"It's terrible. You just had to uproot your life," said Luster, 28. "We have to live by other people's rules and regulations. It's difficult being around people you don't know."

The Associated Press contributed to this report.