We continue to watch the potential for significant river flooding as early as this weekend. Heavy rainfall combined with 1-2" of additional 'rain water' from snow melt will test some local rivers. This is a threat that shouldn't be over looked but this article will focus on the long-term potential for flooding this next few weeks.
A number of factors point toward the flooding threat not being confined to only around this weekend but the next several weeks.
1) Ice will remain on local rivers and Lake Erie
2) The snow will not completely melt
3) Another cold-snap is likely
Ice on local rivers has been measured at 16" near Grand Rapids on the Maumee and 12" near Findlay on the Blanchard. While the warm-up and rain will thin out the ice to some extent, it will not be enough to completely melt this ice. Combine the river ice with the fact that the western end of Lake Erie is still very much covered in ice and the threat for ice jams will persist, especially on the Maumme. When ice from the Maumee tries to flow downstream it will be slowed by any ice remaining near the mouth to Lake Erie.
You may have noticed it already -- the snow is melting but it's not simply disappearing. It will take time to melt this deep and widespread snow pack. Rainfall on Thursday will certainly help and much of the snow will melt. But again it likely will not be enough to completely remove the snow pack. That means when cold air returns, there will still be some moisture sitting and waiting for the next warm-up. (Although much reduced from where we started this week)
As was hinted at earlier, another cold snap is likely by the middle of next week and into March. That will allow the ground to remain frozen, ice to build back up on rivers and any remaining snow to stick around. While not a foregone conclusion this does prime the potential for more flooding down the road when a more permanent warm-up returns along with the inevitable March rains.