Flood — Columbia, Pennsylvania

2011-09-07 to 2011-09-11 · near Catawissa, Columbia, Pennsylvania

Event narrative

The Susquehanna River at Bloomsburg crested above record/major flood stage at 32.75 feet. Widespread flooding was reported in the Bloomsburg area.

Many roads were closed due to flooding from creeks and streams especially over the southern portion of the county. In Hemlock Township, Hemlock Creek overflowed its banks. A bridge on Dahl road was closed to traffic. Mainville and Mifflinville areas were pretty much isolated due to numerous road closings. In the village of Eyers Grove near Millville, water from Fishing Creek flooded the neighborhood. Water rescues were reported in the area. In Greenwood Township, Fishing Creek was a few feet away from Route 42 and was shut down.

Helicopter rescues were performed in Bloomsburg. More than a dozen residents living in a flooded section of West Main Street in downtown were stranded after Fishing Creek spilled its banks. Interstate 80 was also closed from Bloomsburg to Buckhorn, again after Fishing Creek spilled its banks. There was significant flooding in Bloomsburg. The Bloomsburg Fair, the largest fair in the state, was cancelled for the first time in its 157 year history. The fair grounds were under 10 to 12 feet of water.

Water plants were shutdown in Bloomsburg with a loss of water to 5000 customers. Multiple homes were reported washed away in Hemlock Township. Knoebels Amusement Park also took the flood hard with buildings reported knocked off their foundations.

A preliminary total of 21 structures were destroyed, 438 suffered major damage, and 140 suffered minor damage with a total of 868 structures impacted. Damage was estimated at $15,587,737 for public facilities.

Wider weather episode

Heavy rainfall from the remnants of Tropical Storm Lee produced widespread flooding, flash flooding and river flooding mainly near and to the east of the Susquehanna Valley from September 4-10. Several locations in the Susquehanna Basin came close to records set by Hurricane Agnes (June 1972) and a few points (Bloomsburg, Hershey and Loyalsockville) set new floods of record. Flooding along Swatara Creek resulted in property damage and several deaths. Severe flooding occurred along Loyalsock Creek and many points along the main-stem of the Susquehanna River. The interaction of a stalled frontal boundary over the Mid-Atlantic region, a strong northern stream short-wave (with a persistent jet entrance region) and deep tropical moisture associated the remnants of Tropical Storm Lee resulted in multi-day, significant heavy rainfall event over Pennsylvania.

Tropical storm Lee was the twelfth named storm of the 2011 season forming over the Gulf of Mexico on September 1. A strong northern stream short-wave interacted with Lee causing the storm to re-curve to the north-northeast. By 1200 UTC September 6, having undergone extra-tropical transition, post-tropical Lee was located over northern Georgia. The surface low weakened as it moved up the Appalachian Mountain chain. However, the strong low-level flow and the above normal precipitable water produced an extensive, north-to-south oriented band of heavy rainfall.

The rainfall associated with the remnants of Lee produced the 4th largest flood of record in the Mid-Atlantic Region. The five-day storm rainfall totals for September 5 to 9 were generally in the 5-8 inch range over the mid-section of central Pennsylvania and in the 8-12 inch range in the Susquehanna Valley region. There were local amounts reported in excess of 15 inches east of the Susquehanna River. The local climate sites in Harrisburg (KMDT) and Williamsport (KIPT) reported 13.44 and 9.03 inches respectively. On September 7, 2011 both KMDT and KIPT set their all-time daily (24-hour) rainfall for the month of September at 7.71 and 6.76 inches respectively. These sites later went on to break the all-time monthly (September) and annual precipitation records, making 2011 the wettest year on record.

View location on OpenStreetMap → (40.9255, -76.4800)

Source: NOAA Storm Events Database, event_id 348407. Narrative written by the NWS forecast office that issued the report.