MISSOULA, Mont. -

It's official: Montana weather forecasters say flood season has officially arrived.

Blame the nice weather. High temperatures are expected throughout most of western Montana for much of the coming week.

"We are looking for some rapid rises in some of these smaller streams,? said National Weather Service Meteorologist Mike Johsnon. ?It is possible that some of them will be flooding; we'll see some field flooding, pond flooding, and things like that. We're just asking people to be aware of that."

Johnson said they're already starting to see a rise in some of the region's smaller streams. That water will eventually make it to the larger rivers, and may cause a significant rise in flow levels.

Officials are most concerned about the streams and rivers in northwestern Montana, especially the Yak River near Troy, the Bitterroot River near Libby, and the Stillwater River in Kalispell.