It’s frigid but not entirely frozen down at the extreme lower end of the non-tidal Delaware River. Chunks of ice were floating by the Calhoun Street Bridge in Morrisville this morning.
An essential tool for those interested in rivers and creeks is the NWS Hydrology page (this links you the Mt. Holly station). There you find the ANNUAL WINTER/SPRING FLOOD POTENTIAL STATEMENTS and much more (ice buildup, snow cover etc.).
Right now the flood potential is deemed to be “above normal.” Just a few days ago the Delaware River at Riegelsville gage surged to almost 16 ft. (six feet below flood stage). The river continues to run well above the median flow for January 30 at the Belvidere gage (15,000 cfs compared to 5,000 cfs).
The tributaries are running a bit above normal but that should change over the next string of dry days.
While we typically have little to no ice buildup on the lower Delaware River (with huge exceptions like the Winter of 1996 Ice Flood) the more telling ice and snow statements come from NWS’s Binghampton, NY station, which covers all of the Upper Delaware River.
As of this weekend there is little snow pack in the upper watershed, although thick ice covers the large eddies in the Pocono/Catskill reach of the river. Ice buildup sets up one of the conditions needed to cause a specific type of flood along the Delaware. A quick thaw and heavy rain on top of snow pack and ice jams can create a serious threat to communities along the river. The NYC reservoirs have no impact on this particular flood scenario.
With luck the coming spring thaw will happen gradually without any big storms so we don’t have a repeat of the April 2005 flood.