Gary Stoller, USA TODAY

The number of people unaccounted for in flood-ravaged Colorado rose Sunday to about 1,000 as flooding spread to 15 counties and rain continued to fall.

Many of those unaccounted for were reported unreachable on the phone by family members.

"We don't expect to find 1,000 fatalities," said Micki Trost, a spokeswoman for the Colorado Division of Homeland Security and Emergency Management.

Four fatalities - three in Boulder County and one in El Paso County - have been reported.

About 14,500 people have evacuated from flooded areas in 15 counties, and 1,329 stayed overnight Saturday in 28 emergency shelters, Trost said.

Many displaced residents are staying with family or friends or in hotels, she said.

Rain fell intermittently Saturday, and 4 inches of rain were expected Sunday.

Colorado Gov. John Hickenlooper said Sunday he expects the weather to clear Monday morning or afternoon.

The state has "a lot of broken roads and broken bridges, but we don't have broken spirits," he said.

Hickenlooper said helicopters rescued more than 2,000 people in need of evacuation in flooded areas.

The size of the flood-affected area is growing.

Flooding has impacted the foothills on the eastern slope of the Rocky Mountains from Fort Collins in northern Colorado to Canon City, about 180 miles away in southern Colorado.

The hardest-hit counties are Boulder and Larimer in the north and El Paso in the south. The state's two largest public universities are in the two northern counties - the University of Colorado in Boulder and Colorado State University in Larimer's most populous city, Fort Collins.

In El Paso County, which includes Colorado Springs, the Manitou Springs area has been most affected by the flooding, Trost said.

Floodwaters have now spread east to the Great Plains in eastern Colorado. An emergency shelter has been set up in Sterling, about 102 miles east of Fort Collins and the Rocky Mountain foothills.