Flood Watch

[CanisLupusArctos]

This thread is for the monitoring of the spring flood situations, 2009.

The National Weather Service has issued a flood watch for the entire state of NH except extreme southwest (Keene area) and the entire state of Maine for the storm that is moving into the area this afternoon. The lake level has been rising all week.

A great deal of rain is now moving up from the south. This is the eastern (warm) side of the winter storm that is bringing heavy snow from the Great Plains eastward to Chicago, where baseball's opening day has been snowed out. The storm is drawing unseasonably cold air out of Canada and wrapping it around to the south where the cold front is touching off severe weather -- tornado watch in effect as far north as Virginia.

On the east side of the storm (ours) the low pressure center is pulling moisture and warmth up from the south, into the path of the cold air wrapping around from the north. This interaction is milking the moisture out of the air in the form of heavy rain and thunderstorms, which will be our weather later today and tonight.

The heavy rain combined with mountain snowmelt may make rivers go over their banks. If that happens, you will hear of a flood warning for the rivers affected, broadcast on radio or TV.

The rivers and the lake will continue to rise after the rain has stopped, as runoff finds its way in.

[SAMIAM]

Thanks for the heads up....looks like you hit that one right on the money.

[CanisLupusArctos]

The lake is now within an inch or two of full pool. Iceout is likely this week based on the trend I've been seeing - the combination of wind, rain, and sunny/warm weather on the ice. The melt has been occurring slowly this year, and continues that way.

[Resident 2B]

Adding to the rapid rise in the lake are the high water levels downstream in Silver Lake and Winnisquam forcing the dam operators to reduce Winnipesaukee outflow twice the past two days. Outflow is now at 1,265 CFS, which is down from 1,800 CFS, with the estimated inflow at 3,700 CFS.

The folks at the Dam Bureau are increasing the flow at the Lochmere Dam to 1,900 CFS today and that should reduce the level of Winnisquam a bit. The level at both Silver Lake and Winnisquam will need to drop some before the flow at the Lakeport Dam can be increased.

Looking at the flow rates, until they can increase the Lakeport outflow, we will be adding about 2,500 CFS to Winnipesaukee, which is a lot of water. Winnipesauke will continue to rise until the Lakeport Dam flow can be increased.

What we do not need right now and for the next week is a heavy rain storm. The Friday night into Saturday system looks like it will be heavier in southern New England than in the Lakes Region. It will likely start as snow :eek: in the Lakes Region on Friday night and change to rain on Saturday. If this happens, the snow should absorb a lot of the rain spreading the effects of the system out over several days unless the rain washes away all the snow.

The people at the Dam Bureau have a very tough job doing this balancing act.

R2B

[Resident 2B]

The weather system for Friday and Saturday looks to be going mainly south of us with very little rain/snow. The flow at Lakeport has been increased to 1,500 CFS. The lake is now within a tenth of a foot of "full pool" by my gage and it is still rising, but at a much reduced rate.

The increase in outflow and the rather minor rain/snow event for Friday night into Saturday are all good news. However, it looks to me that we will go over "full pool" by some amount.

R2B

[gtxrider]

The lake flooding, fire in Alton Bay what's next? :(

[Resident 2B]

There is some good news in that the lake has not flooded yet, and it is looking like we are into a dry spell that should result in a drop in lake level this week. Looking at my dock, I think that drop has already begun.

The lake level was rising rapidly to just about full pool. It then stopped rising and looks to be dropping a bit.

Too bad about the fire in Alton Bay. Tough time, especailly on Easter Sunday.

R2B