Flooding Now vs. The 1936 Johnstown Flood

I haven't had time to research this thoroughly but I wanted to get some thoughts out on the upcoming flooding (starting today and going through next week) in the Northeast Quadrant of the country. Here are some talking points, feel free to leave Comments below.

1. There is significant snowpack in the Pennsylvania and New England, and there is heavy rain coming to the area. But apples to apples for the Johnstown area, we're not anywhere near the same situation as the famous 1936 Johnstown Flood which I blogged about two years ago. Then, they had a snowpack of approximately 9 inches of water equivalent, and were hit with 7 inches of rain. In the surrounding area, the USGS claimed up to 30" of total rain equivalent was released.

Here in 2011, we're looking at a snowpack of 4-6 inches in the areas (shown above) where 2-4" of rain will fall over the next few days (shown below)

2. While the 1936 Johnstown Flood problems have been since mitigated by channelizing the rivers (and also the flooding in Wilkes Barre caused levees to be built), flooding is a very site-specific disaster and it's hard to predict based simply on the amount of water that is released from the ground and atmosphere. It's unlikely either of those places could be hit this time around, but somewhere else might.

3. We are working on an interview for this weekend, where we talked to a local hyrdrologist. He has pinpointed Ohio as the potential big problem area, according to their models. But Ohio hardly has any snowpack, you might note. True, but their 30-day precipitation has been above normal (as has western Pennsylvania's, which is interesting) while most of the rest of the area has been below normal, as you can see from the map above.