EF2 Tornado — Washington, Pennsylvania

2021-10-21 · near Independence, Washington, Pennsylvania

Event narrative

A NWS damage survey confirmed that an EF-2 tornado, with winds

peaking near 130 MPH, tracked through western Washington County

on the evening of October 21, 2021. The length was over 15 miles

long and the width varies in some areas but the maximum was between 600

to 700 yards. This tornado was associated with the same circulation

that initially produced a tornado in Jefferson County, Ohio earlier.

Weak tornado damage was first noted along Brashears Run Road with

a few fallen trees. The storm rapidly intensified along Indian

Camp Rd, where a mobile home had roof damage and a well-structured

deck was ripped and tossed into the neighbors yard. Many trees

were snapped and uprooted as well. Damage in this area was

consistent with winds speeds of 90-95 MPH.

The tornado continued east towards Hopewell Township. Noted roads

that had tree and structure damage, associated with EF-1 damage,

were along Short Cut Road, Scenic Drive, Raccoon Run Road, Possum Hollow

Road, Old Trail Road, Jefferson Avenue, Park View Drive, and

Oakleaf Road.

Peak intensity was reached near Willow Road and Lowry

Lane where a two story home had a roof completely torn off and

tossed about 100 feet and a few portions of the walls collapsed.

With closer inspection, a few of the foundation blocks were

shifted on both sides of the house. Peak wind was near 130 MPH in

this region. A few hundred feet away a farm building was

completely destroyed. As the tornado crossed Lynn Portal Road and

advanced along White Lane, a solid brick home lost the roof and

the attached garage.

The tornado started to weaken, but still continued to hold near

100 MPH winds, as it tracked across McCarrell Road, Western Ave,

and towards the outskirts of the city of Houston, PA. The tornado

appears to have dissipated near North Main Street and Pine Ave

north of Houston, PA.

At least $600,000 of damage was noted by PEMA to four different structures.

The total cost of destruction was estimated by the NWS Storm Surveyor.

Wider weather episode

A broken line of supercells, which formed along a front, moved quickly through the Ohio River Valley the evening of October 21st and spun off several tornadoes. The number of tornadoes, time of year, and intensity (one long track EF2 tornado) will mark this event as very rare and significant for this region.

Prior to tornado development, surface temperatures warmed into the low-mid 60s; dew points topped out near 60F. Forecast soundings indicated modest levels of mean layer CAPE, and a relatively straight hodograph yielding marginal but sufficient storm relative helicity. The overall quick track of the broken line and eastward propagation helped cells sustain rotating updrafts.

View location on OpenStreetMap → (40.2283, -80.5070)

Source: NOAA Storm Events Database, event_id 987923. Narrative written by the NWS forecast office that issued the report.