BILLINGS, Mont. - Emergency workers ferried supplies to more than 300 people cut off Friday by flooding that has overwhelmed Montana towns and caused an estimated $8.6 million in damages to date.

Heavy rain and the runoff from record mountain snowpack have caused rivers over much of the West to spill from their banks. Montana has been hit particularly hard over the past few weeks, with hundreds of homes inundated and scores of roadways swamped.

River levels were retreating throughout the state on Friday, but more rain this weekend was expected to cause flood waters to linger across southeastern Montana.

There, roads washed out by the raging Musselshell River left people in a sprawling rural neighborhood in the hills outside the town of Roundup with no way to get out.

Stranded residents were able to call in grocery orders that emergency officials delivered by boat, said Cassie Degner, a local volunteer firefighter. A trailer filled with water, diapers and other essentials had been brought into the neighborhood before access was lost Wednesday.

Mary Brower, 81, said she had not been able to get into town since May 20 and the roads have further deteriorated since that time.

"They're going to bring in my medications today by, I don't know, rowboat or whatever," said Brower, who suffers from congestive heart failure.

Up the road from Brower, rancher George Smith said he and his wife, Loris, were rationing gasoline but otherwise planned to get by with "a few cans of different stuff we have on hand."

"My wife makes corn bread and I'm a bean maker," Smith said. "We might get to fighting a little bit, but we're good for another week anyway."

Authorities in Roundup began pumping out a portion of the downtown that has been swamped twice since the Musselshell started to rise in late May. Workers also were scrambling to rebuild a makeshift dike along the edge of town that was overtopped and severely eroded earlier in the week.

The main highway out of Roundup to Billings reopened Friday after being closed for two days when it was under water.

Repairs on the road into the cut-off neighborhood were not expected to begin for several days because portions of it remained under water, said Musselshell County Commissioner Sue Olson. Another boatload of groceries and other supplies was to be ferried into the neighborhood Friday evening.

The Musselshell River was forecast to drop slightly Friday before rising again to stay above major flood stage until today.

"As soon as the water comes down it comes back up. We're at the mercy of the river - and it's not so forgiving lately," Degner said.

Gov. Brian Schweitzer estimated the flooding has caused more than $8.6 million in damage across the state since the end of May.

That figure was included a Thursday letter to President Barack Obama in support of a previous request for a disaster declaration. Schweitzer's office said it could rise with additional damage.

The request for federal assistance covered 31 Montana counties and four Indian reservations. Schweitzer, who is traveling in China, reviewed the letter before it was sent to Obama, spokesman Jayson O'Neill said.

Crews in eastern Idaho have lined sandbags around areas prone to flooding as steady showers and the melting snow caused flooding in lowland farm fields.

Idaho Gov. Butch Otter flew over three eastern counties Thursday to get a sense of the flooding and meet with local officials bracing for rivers and creeks to swell even more. Last month, Otter signed a disaster declaration for Jefferson, Madison and Bingham counties, allowing officials to tap the state for sandbags, water pumps and technical support.

Several Montana rivers hit record levels this week. While many were receding Friday, flooding is ongoing in the basins of at least 10 major rivers across Montana.

The melting snow and rain caused the Army Corps of Engineers to release water from the Fort Peck Dam into the Missouri River at a record 60,000 cubic feet per second. That sent torrents of water gushing downstream, flooding low-lying areas of the Fort Peck Indian Reservation and adding to flood pressures in North and South Dakota.

The U.S. Department of Agriculture on Friday said it would provide $600,000 each to Montana, Colorado, Idaho, Utah and Wyoming to be used immediately for emergency restoration projects.

Agriculture Secretary Tom Vilsack said in a statement the funding targeted states where the record snowpack poses flooding risks. The money will be used for projects that could include removing debris caught in culverts and under bridges and efforts to prevent soil erosion.

In Utah, the National Guard used helicopters Friday to help fix a 30-foot-wide break in a levee that has begun flooding west Weber County.

The levee separating the swollen Weber River and a small canal broke Thursday, and troops at the site about 10 miles west of Ogden were putting 50 one-ton sandbags into place, said Weber County Sheriff's Lt. Mark Lowther.

The river is expected to remain above flood stage through the middle of June. Residents in the area already have sandbagged their homes but fear the worst after seeing their yards inundated.

In Colorado, the Colorado River was flooding near Rifle. Officials in Greely closed several roads because of high water and debris. And turbid waters prompted officials to partially restrict access to the Cache la Poudre River.

The Larimer County sheriff's office said Friday that inner tubes, some types of air mattresses and small inflatable rafts have been banned from the river until the waters calm down. Restrictions could stay in place until early July.

In northern Wyoming, the Bighorn River was rising rapidly near Basin after more than 2 inches fell in the region. Some low-lying areas there were expected to flood Friday.