RECORD-SETTING LANDSLIDE YEAR IN THE GREATER PITTSBURGH AREA, PENNSYLVANIA: 5 YEARS LATER

In 2018 the Greater Pittsburgh region experienced record rainfall (57.83 in) and landslides (over 200). Beginning in an unusually warm, rainy February, landslides disrupted roadways, and other infrastructure and moved and damaged houses and apartment buildings. A declared State Emergency allowed support for emergency response.

Preliminary damage estimates were over $22 million from 173 landslides from February through April in Allegheny and Westmoreland Counties. Less intense rain continued through the year producing at least 20 more landslides. Including portions of adjacent counties brings the total for the year to well over 200.

Most of the 2018 slides affected infrastructure ranging from small shallow debris slides that blocked one lane to the major US Rt. 30 failure which destroyed a four-lane commuter route. That repair was fast-tracked and accomplished in 3 months with costs exceeding $10 million. Many lesser roads were closed for months or years. Over 50 private residences were damaged or evacuated and 18 are known to have been destroyed or demolished. Access to other homes was limited by damaged roads, sometimes for months.

This extraordinary series of events has led to increased focus on landslide hazards. The Pennsylvania Emergency Management Agency held workshops on recognition and response and featured landslides in their monthly newsletters. Allegheny County created an information portal. A university-based transportation and infrastructure collaboration prioritized landslide projects. The 2023 revision of the State Hazard Mitigation Plan will include increased attention to landslides.

PennDOT, Allegheny County Public Works, the City of Pittsburgh and other municipalities all had backlogs of landslides waiting for repair at the beginning of 2018. Many 2018 slides are still among those on the current or pending project lists. But budgets for repair have increased and the backlog is steadily declining. Relatively dry recent years with low numbers of new landslides have helped.

Landslide problems will continue with climate change induced precipitation patterns. New attention may help local governments develop policies to reduce hazard and there is renewed interest in legislation to provide insurance or assistance for homeowners. There is reason to be hopeful following the lessons from 2018.