Warm Winter Bonus: Spring Flood Threat Low In Much Of The Northeast

Ice jams like this one on the Lamoille River near Johnson, Vermont
caused some flooding on February 25. But with a very low
snowpack and following a record warm witner,
the risk of severe spring flooding in Vermont this year is low. 

Continuing a trend we've seen all winter, there's not much snow on the ground right now in most of Vermont and northern New York.

At my house in northwestern Vermont, there's pretty much nothing.

Atop  normally buried Mt. Mansfield, the snow depth as of Sunday was only 34 inches.  At this time last year, the snow on Vermont's highest mountain was 79 inches deep.

This is surely frustrating all the skiers and winter sports enthusiasts out there, but there is at least one silver lining. It looks like the threat of spring flooding is pretty damn low.

The National Weather Service office in Burlington, Vermont every other week puts out a spring flood  forecast based on condition so far this season. The latest statement say the spring flood potential ranges from below normal to much below normal.

Unless we're surprised by a bout of winter weather that brings record amounts of snow in March - which looks highly unlikely at this point -  there's not much snow melt available to run off into rivers.

The amount of ice on rivers is low, too, because it's been such a warm winter, says a the latest flood potential outlook from the National Weather Service in South Burlington, Vermont.

Back on February 24 and 25, there was a record heavy rainstorm, which broke up what little ice there was on Vermont's rivers. That led to some damaging floods in a few spots, especially around Hardwick and Springfield, Vermont.

There's not much ice left out there. Oh, sure, March has started on a pretty cold note, and some river ice has formed again. But the ice isn't that extensive, so most Vermont and northern New York rivers probably won't see any huge ice jams as the month progresses.

Rivers are running somewhat higher than normal for this time of year, thanks to all that rain in February. Soil moisture is a nit above normal. So is the Lake Champlain lake level,  again because of all that winter rain that by rights should have come down as snow.

With the relatively high water and moisture levels, you'd think the spring flooding potential would be at or above normal.

But remember, the snow cover is way, wayyyyyy below normal in northern New England for this time of year. There's not much available to drain into rivers and lakes when more thawing weather arrives. Which means don't count on much spring flooding.

That thawing is due to start in earnest basically now.  Temperatures will get into the 50s and maybe even low 60s by Wednesday before settling back a bit at the end of the week. That tiny bit of snow out there will melt quite a bit, but it won't have much of an effect on river and lake levels.

We might end up getting a fair amount of rain in Vermont over the next week, as much as an inch and a half of it, but it won't be enough to cause any real flooding.

Long range temperature trends favor above normal temperatures for the rest of the month in the Northeast, and also maybe above normal precipitation.

But unless that precipitation is extraordinarily heavy, don't count on much flooding.

Still, don't completely count the possibility of flooding out. There is always the slight possibility that incredibly heavy rains could end up falling in late March, April and May. That's not a forecast, but it's a caution that it could happen, even if the chances of it are slim.

There is precedent for a warm, snow-free winter that still ended in spring flooding.

 In the winter of 1982-83, Vermont and the rest of the Northeast had an El Nino driven warm, relatively snow-free winter like this one.  It wasn't as snow-free as the current El Nino winter, but still.

In March, April and May of that year, tremendous amounts of snow and rain fell on Vermont and New York. That led to some river flooding, and set a record for the highest flood on Lake Champlain. That record was later broken in 2011, after an extraordinarily snowy winter and a record rainy spring.

The bottom line is, there's always the possibility of flooding in Vermont from particularly rainy episodes, but the way things are going now, I'd blow off that plan to build an ark.