The beauty of recent snows may get reassessed across southern Minnesota this weekend as a half-inch of rain, along with snow and above-freezing temperatures, may turn some roadways into waterways.
Some urban flooding is expected as rain and snowmelt head for sewers that are still clogged with ice and snow. The National Weather Service issued an alert Thursday for possible localized flooding Saturday and Saturday night for the metro area and southeastern Minnesota. Some flash flooding also could occur as water flows over frozen ground and down steep hillsides into southeastern Minnesota streams and rivers.
For the longer term, new snow has increased the likelihood of spring flooding along the Red River in northwest Minnesota, but the risk of river flooding in the Twin Cities metro area remains slight, the National Weather Service reported Thursday.
The snow early this week, nearly a foot in many places, added nearly an inch of water to the landscape along the Red River Valley. That has left nearly 5 inches of water sitting above ground in scattered areas around the headwaters of the north-flowing Red and the south-flowing Minnesota River, which meets the Mississippi in the Twin Cities.
The Weather Service noted that above-normal snowfall is expected in northern Minnesota in the coming weeks, and frozen soils beneath the snow will prevent some meltwater from soaking into the ground. For flood-prone Fargo, N.D., the chance of a river rise that would require downtown diking is about 80 percent, though the chance of a top 10 flood is 30 percent at most.
Areas around the headwaters of the Mississippi also hold more than 5 inches of water, but National Weather Service hydrologist Diane Cooper said the marshy landscape and lakes that have been at low levels will be able to hold some of that back. As a result, the chances of flooding along the Mississippi and Minnesota rivers are considered normal.
At St. Paul, there is currently a less than 5 percent chance the Mississippi could shut down Warner and Shepard Roads near downtown. The chance that water could encroach on Interstate 35W near Burnsville is less than 2 percent.
But chances that the Bloomington Ferry Bridge and trails at Fort Snelling State Park could see closures are expected to be slightly higher.