Undated (AP) _ Heavy rains in Missouri forced evacuations in Kansas City on Thursday and were blamed for one death, while showers, thunderstorms and lowland flooding ranged across southern Illinois into the Ohio Valley.

Snow piled up on the higher elevations of the Sierra Nevada and Rocky mountains.

Chest-high water stranded cars and flooded low-lying streets in Kansas City before dawn Thursday after a slow-moving storm dumped more than 6 inches of rain on parts of the city.

The Blue River in the eastern part of the city continued rising Thursday, and police ordered the evacuation of a trailer park and an industrial area. They had no estimate on the number of people affected.

The Missouri Highway Patrol blamed a traffic death near Warrensburg, Mo., on Wednesday's heavy rain. A man was struck by a car as he stood along a highway during a downpour.

The Little Blue River in Lake City, Mo., was 6 feet above flood stage at noon Thursday and beginning to recede, but the Big Blue was not expected not crest until late Thursday.

A flash flood watch was posted for southern Illinois, where some streets were awash by thunderstorms that dumped nearly 8 inches of rain on Chesterton in 24 hours, with 2 to 6 inch amounts common across the watch area.

Many areas near the Ohio and Wabash rivers of southwest Indiana received 2 to 4 inches of rain overnight.

Thunderstorms were widely scattered from southeastern South Dakota across eastern Nebraska, where many streams were at capacity, and into northeastern Kansas, where flood warnings issued for Stranger Creek and the Delaware River basin.

People in Wyoming's eastern Laramie County were warned to take shelter as a thunderstorm dropped hail up to three-fourths-of-an-inch in diameter in Carpenter, about 30 miles southeast of Cheyenne.

Streams were near bankfull in southeastern South Dakota and locally heavy rains were possible again Thursday night.

Travelers advisories for snow were in effect for the higher elevations of the Shasta, Siskiyou and the northern Sierra Nevada mountains.

Snow was also reported along the eastern slopes of the northern Rockies above 8000 feet, and up to 1 foot of snow fell on the upper reaches of the Teton Range in Wyoming overnight.

President Reagan declared a disaster for Michigan because of storms and flooding that killed five people and caused damage to 13,000 homes beginning on Sept. 10, the White House announced as Reagan campaigned in Montgomery, Ala.

The Federal Emergency Management Agency immediately designated people in 22 Michigan counties eligible for federal disaster aid and said application centers will be opened in the flood-damaged region within about four days.

Central Michigan University, which suffered an estimated $2 million to $4 million damage, held classes for the first time in a week.

Elsewhere, showers fell on the Northern Pacific coast and across parts of the northern and central Rockies and the northern High Plains, and thunderstorms were scattered from southeast Texas across the lower Mississippi Valley, and over Florida and Georgia.

Temperatures around the nation at 3 p.m. EDT ranged from 33 degrees at Lewistown Mont., to 97 degrees at Cotulla, Texas. The low for the nation this morning was 23 degrees at Gunnison, Col.

The national weather forecast for Friday predicted showers and thunderstorms over the Ohio Valley, with widely scattered thunderstorms from southeast Texas across the Gulf Coast and parts of the southern Atlantic Coast, the southern Appalachians, Arkansas and Oklahoma. Scattered showers will extend across much of the northern half of the nation, more numerous from the northern Plains to the upper Great Lakes.

High temperatures will be in the 50s from the northern Rockies across North Dakota to upper Michigan, and in the 90s over the desert Southwest, the southern Plains and the lower Mississippi Valley.