Synoptic and mesoscale analyses of the meteorological conditions that produced disastrous flash flooding in the Johnstown, PA., region on July 19-20, 1977, are presented. Detailed rainfall analyses based on surface rain gauges, National Weather Service (NWS) radar, and satellite rainfall estimation techniques are also shown. Dynamic processes associated with a weak short-wave trough triggered and maintained widespread thunderstorm activity over Pennsylvania and New York during the afternoon and evening of July 19. Two major squall lines moved across Pennsylvania. The western extension of the outflow boundary produced by the second squall line became quasi-stationary in western Pennsylvania, and appeared to be the primary feature that focused the heavy rainfall over a relatively small region. Warm, moist air was lifted over the rain-cooled air lying north and east of the boundary, triggering new storms in the same general region. The storms repeatedly moved southeastward over the Conemaugh River Basin, producing 8- to 9-h rainfalls of up to 12 in.

Excerpt from Johnstown-Western Pennsylvania Storm and Floods of July 19-20, 1977 At least 78 deaths were attributed to the floods, and eight persons were still listed as missing 1 year later. Total damages in the eight county flood area were extremely high and might exceed $330 million. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.