Key Features

HURREVAC (short for Hurricane Evacuation) is a storm tracking and decision support tool. The software combines live feeds of tropical cyclone forecast information with data from various state Hurricane Evacuation Studies (HES) to assist the local emergency manager in making evacuation decisions based on the timing and potential severity of storm effects such as wind and storm surge.

Software access is restricted to officials in government emergency management. As a general rule, you are eligible to use the HURREVAC program if you are affiliated with:

  • emergency management for a county, parish or locality in hurricane-prone U.S. states and territories including, Puerto Rico, the U.S. Virgin Islands, Guam, CNMI, and American Samoa,
  • state, territory, or tribal emergency management agency (EMA),
  • FEMA,
  • USACE,
  • NOAA and National Weather Service offices.

The software is distributed free-of-charge to eligible users who register here.

Baton Rouge, LA, October 3, 2002 -- The Emergency Operations Center is staffed 24 hours a day during the approach of Hurricane Lili reaching land.

Photo by Bob McMillan/FEMA News Photo

Many Emergency Operations Centers use HURREVAC as a situational awareness and briefing tool.

What can HURREVAC do?

HURREVAC tracks hurricanes using the National Hurricane Center’s Forecast Advisories. The software translates forecast track and wind extent information from the NHC’s text-based products into interactive maps and reports that are used to chart the progress of an advancing storm. Storm surge (SLOSH) model output is made available within the program to assist with awareness of coastal areas vulnerable to seawater inundation. The program also assembles freshwater rainfall, flood, and river forecast information from various sources to assist users in evaluating inland flooding threats.

A critical feature of HURREVAC is its ability to keep to the local emergency manager apprised of how many hours or days a community has for preparation and planning in advance of a threatening storm. As new forecast information becomes available, HURREVAC continually updates and reports on the community’s Evacuation Start Time, or last possible time by which an evacuation could be initiated if it is to be completed before the arrival of the storm hazards.

The decision to evacuate a community is not an easy or obvious one and the advantage of fine-tuning your Evacuation Start Time in HURREVAC is that you can base decisions on the closest (and therefore most accurate) projections for the storm track, intensity, and size.

HURREVAC cannot make the evacuation decision for you. It is merely one tool that you may elect to use to help you in the hurricane decision-making process. Evacuation decisions are very complex and should only be made after consultation with all officials involved in the process, from NHC and the National Weather Service, to state and local emergency management officials.

How is the Evacuation Start Time calculated?

HURREVAC calculates Evacuation Start Time using input from the official hurricane forecast and the Hurricane Evacuation Study for the county or parish of concern.

The NHC’s Arrival of Tropical-Storm-Force Winds product is utilized for determining how soon within a 5-day forecast period the hazards may begin in the jurisdiction. Two hazard start times are offered for the emergency manager’s consideration: a conservative ‘earliest reasonable’ time of wind onset and a less conservative ‘most likely’ time of onset.

A clearance time scenario is selected by the emergency manager using guidance provided in the Hurricane Evacuation Studies (HES) documents for the region. This selection is typically guided by identifying which evacuation zones delineated in the HES process have potential for storm surge inundation given the present storm forecast. A number of other real-time factors (tourist population and public response, for example) may also influence the selection of a specific clearance time scenario.

Evacuation Start Time is reported as a range from ‘Earliest’ to ‘Latest’, based on subtracting the number of hours in the Clearance Time Scenario from the ‘earliest reasonable’ and ‘most likely’ hazard onset times.