The weather front forecasted to douse the area with rain, sleet and snow today and tomorrow won’t likely cause ice-jam flooding, according to the National Weather Service — at least not right away.
Starting this morning and running through Thursday, the Capital Region and Mohawk Valley are expected to see rain and up to 6 inches of snow, while as much as 20 inches of snow may fall in the Adirondacks.
It’s been a long, cold winter. With thick ice over parts of the Mohawk River and its tributaries and significant snow accumula-
tions in the area, the most recent hydrologic outlook released by Weather Service experts predicts an increased risk of springtime ice-jam flooding.
According to National Weather Service meteorologist George Maglaras in Albany, the wet forecast won’t cause any immediate flooding.
“There are a number of factors,” he said.
Right now, there might be some thick ice in the Mohawk, but there’s not enough water beneath it to wreak any havoc. Maglaras said water levels would have to rise between 1 and 3 feet to break loose the sheet ice and send it downstream to pile up at locks and bridges, and send a flood of spring melt over riverbanks.
“We’re not forecasting that much of a rise,” he said.
Such a rise, he said, requires both warmth and rain. While the area is forecasted to get rain and above-freezing temperatures today, Maglaras said there won’t be enough of either to cause problems.
The mercury is expected to drop into the teens by Thursday and stay relatively low for days. That will stall any melting. As for the rain, Maglaras said, most of that will get sponged up by existing snowpack. That’s good in the short term, but could raise the likelihood of flooding later this month or in April, depending when the spring thaw comes.
Maglaras doesn’t see any precipitous temperature rises or torrential rain events in the seven-day forecast, but beyond that he’s not sure what’s coming. The best-case scenario is a slow, gradual warm-up. The ice would melt by fractions, slipping away a little bit each day without incident.
In Montgomery County, divided lengthwise by the Mohawk, officials aren’t planning for the best case.
“If we get a foot of snow,” said Montgomery County Emergency Management Director Jeff Smith, “then next week three 60-degree days, we’ll have some flooding.”
Since January, Smith and a few team members have been monitoring the ice situation on area creeks and rivers.
“We have an ice jam on the Otsquago Creek,” he said. “It’s the size of a football field.”
Right now it’s not a huge problem, according to Smith. The ice is just sitting there with water levels too low to move the blockage along. Given the right weather conditions, that could change in a hurry.
Flooding in that area could hypothetically ruin the progress made by Fort Plain in the past eight months after flash floods devastated the village in early summer. Another flood could do it all again.
“We’re physically monitoring the situation,” Smith said.
So far he’s seen the Otsquago swell and just run to the side of the ice jam, temporarily soaking some trees but no homes.
“It might not even reach the village,” he said. “It’s a few miles south in Minden.”
There’s another small jam where the Canajoharie Creek meets the Mohawk.
Further east, Union College geology professor John Garver has been watching eagle-eyed for potential ice jams where the Mohawk borders Schenectady’s flood-prone Stockade.
“We’re anticipating ice out in the next few weeks,” he said in an email.
If the sort of cooler temperatures forecasted for the next few days persist long enough, Garver suggested the risk of ice jams could lessen.