With spring flooding already underway over portions of the U.S., NOAA forecasters are warning the worst is yet to come. Almost half the country – from the north-central U.S. through the Midwest and the Northeast – has an above-average risk of flooding over the next few weeks, according to the annual spring outlook released today by NOAA’s National Weather Service. This week is also national Flood Safety Awareness Week, and NOAA has partnered with FEMA to encourage residents to prepare for this imminent threat.

The highest spring flood risk areas include the Red River of the North, which forms the state line between eastern North Dakota and northwest Minnesota; the Milk River in eastern Montana; the James and Big Sioux Rivers in South Dakota; the Minnesota River; the upper Mississippi River basin from Minneapolis southward to St. Louis; and a portion of lower New York, eastern Pennsylvania and northern New Jersey.

“For the third consecutive year, the stage is set for potential widespread, record flooding in the north-central U.S.,” says Jack Hayes, director of NOAA’s National Weather Service. “We’ve been coordinating with federal and state partners and high risk communities since December to raise awareness and help them prepare. All the ingredients are in place for major flooding so this situation should be taken very seriously. We’re asking citizens to stay informed and be prepared.”

Warm temperatures in the forecast this week could cause much of the snowpack to melt across South Dakota and southern Minnesota, setting off moderate to major flooding in eastern South Dakota next week. Minor flooding could begin this week on the Mississippi River and its tributaries over southeastern Minnesota and southwestern Wisconsin, leading to moderate to major flooding by early April.

In addition, a series of storm systems are forecast to move across the region during the next two weeks, which could bring additional snow or rain on top of the remaining snowpack. These systems may cause substantial runoff and the beginning of minor flooding in the southern headwater portion of the Red River of the North, eventually leading to major flooding sometime from the last week of March through early April.