Issued: 08/27/2011 11:39 AM EDT Subject: USGS Issues Landslide Alert for Hurricane Irene: PLEASE DISTRIBUTE Forecasted heavy rainfall, including likely intense periods of precipitation, may trigger landslides on moderate to steep slopes and locally elsewhere on landslide-prone slopes in the northeastern United States. The advisory area includes eastern Pennsylvania, New Jersey, eastern New York, Connecticut, Massachusetts, Vermont, New Hampshire, and Maine, but landslides may also occur on other slopes in adjacent states and along coastal bluffs. Some landslides may be damaging and/or pose a threat to life safety and critical infrastructure. The most likely types of landslides triggered by this event will be shallow debris slides and debris avalanches on steep slopes and rock fall, particularly in mountainous areas of the northeastern United States. Locally, debris avalanches, debris flows, and rock falls may pose a threat to life safety. In addition, some areas in the forecast area contain currently active landslides or landslides that have been active in the past few years including earlier in 2011. The forecasted rainfall amounts may lead to elevated pore-water pressures that cause reactivation of some landslides or a temporary acceleration in the velocity of movement. Movement of shallow landslides is most likely to initiate during periods of intense rainfall, but movement of deeper landslides may be delayed as pore-water pressures rise in response to the rainfall. Managers with critical infrastructure or facilities in known landslide hazard areas should make assessments and take appropriate measures, as necessary, to reduce losses in advance of the arrival of the predicted cyclone. Periodic inspections of slope conditions on and adjacent to critical infrastructure, as feasible, are recommended during and after periods of the heavy rainfall.