The Philadelphia Managing Director's Office of Emergency Management (MDO-OEM) prepared the Citywide Excessive Heat Plan in conjunction with key stakeholders to coordinate the response to excessive heat events.
The Citywide Excessive Heat Plan is updated annually, outlines roles and responsibilities, and gives senior-level managers, first responders, and private and non-profit partners, guidance in making the many complex decisions that may be necessary during an excessive heat event.
During summer months, the National Weather Service (NWS) issues a variety of heat-related notifications. These notifications include Excessive Heat Outlooks, Watches, Advisories, and Warnings. The following indicators are closely monitored by the Philadelphia Department of Public Health during and excessive heat event: - Heat Index: The Heat Index or the “Apparent Temperature” is a measure of how hot it feels to a human when humidity is combined with air temperature.
- Humidity: Humidity refers to the amount of moisture in the air. Humid conditions in Philadelphia usually occur when a dome of high atmospheric pressure establishes itself over the western Atlantic, producing a prolonged period of southeasterly through southwesterly winds. This dome of high pressure tends to trap hazy, moisture-laden air near the ground surface.
- Prolonged high average temperatures: Temperatures that hover 10 degrees or more above the average high temperature for the region and lasts for more than 3 days
Philadelphia’s heat warning system is based on more than two decades of regional mortality and weather data. The summers in Philadelphia are hot and humid. Heat waves, prolonged episodes of high temperatures, and high levels of humidity, frequently sweep the City, creating potentially dangerous life-threatening conditions for some. When exposed to high temperatures and humidity, people are susceptible to sunburn, heat edema, heat cramps, heat exhaustion and life-threatening conditions. These heat- related illnesses can be avoided by moving to air-conditioned or well-ventilated areas.
National Weather Service Heat Index
|
Category |
Heat Index |
Responses |
|
Extreme Danger |
130F or Higher |
Heat Stroke or sunstroke likely. |
|
Danger |
105-130F |
Sunstroke, muscle cramps, and/or heat exhaustion likely. Heat stroke possible with prolonged exposure and/or physical activity. |
|
Extreme Caution |
90-105F |
Sunstroke, muscle cramps, and/or heat exhaustion possible with prolonged exposure and/or physical activity. |
|
Caution |
80-90F |
Fatigue possible with prolonged exposure and/or physical activity. |
Operational Overview
The National Weather Service's notification of an Excessive Heat Warning initiates a series of responses from City, non-profit, and private agencies that serve the citizens of Philadelphia. The Philadelphia Department of Public Health coordinates activates during an excessive heat event.
Operational Strategy 1: Education and Preseason Preparedness
This strategy outlines the pre-Heat Season activities carried out to prepare agencies to respond to excessive heat events in Philadelphia and specifically includes:
- Preparation and distribution of public education materials
- Convening seasonal interagency meetings as necessary to review heat responses
- Preparing stockpiles of essential supplies
Operational Strategy 2: Public Notification and Warning
This strategy outlines various public notification, alerts, and warning procedures for excessive heat events and specifically includes:
- A public notification strategy for excessive heat events
- Activation and management of Philadelphia Corporation for Aging's HeatLine
- Summary of Ozone Action Alerts issued by the Air Quality Partnership of the Delaware Valley
Operational Strategy 3: Excessive Heat Response
This strategy details response plans of the City of Philadelphia, non-profit, and private agencies that include:
- Processes for declaring a heat emergency in coordination with NWS
- Deployment of PDPH mobile teams and district environmental health teams
- Summary of activities associated with Code Red activations and summer outreach for homeless persons
- Summary of the procedures for activating cooling centers (air-conditioned facilities that are free and open to the public)
- Process for increasing the number of EMS resources available for response
- Operation by the Philadelphia Fire Department of the Recreational Sprinkler Program
Philadelphia's Heat Emergency Cooling Locations
Find the location and contact information of cooling centers throughout the City on the Evacuation Routes and Emergency Facilities Interactive Map:
Operational Strategy 4: Utilities
This section outlines the roles and responsibilities of utility companies that provide service in Philadelphia during an excessive heat event and specifically includes:
- Roles and responsibilities of utility companies regarding halting service suspensions due to non-payment
Weather Words
- Excessive Heat: Excessive heat occurs from a combination of high temperatures (significantly above normal) and high humidity. At certain levels, the human body cannot maintain proper internal temperatures and may experience heat stroke. The "Heat Index" is a measure of the effect of the combined elements on the body.
- Excessive Heat Outlook: Issued when the potential exists for an excessive heat event in the next 3-7 days. The purpose of issuing an Outlook is to provide information to those who need considerable lead time to prepare for and Excessive Heat Event, such as public health officials, emergency managers, and public utilities.
- Excessive Heat Watch: Issued when conditions are favorable for an Excessive Heat Event in the next 12-48 hours. This is used when the risk of an Excessive Heat Event has increased but its occurrence and time frame are still uncertain. The purpose is to allow those who need to set plans in motion enough lead time to do so.
- Excessive Heat Warning/Advisory: Either of these may be issued when an Excessive Heat Event is expected in the next 36 hours. These are issued when an event is occurring, is imminent, or has a very high probability of occurring. A Warning is used for conditions posing a threat to life or property. An Advisory is for less serious conditions that cause significant discomfort and if caution is not taken, could lead to a threat of life and/or property.
- Heat Index: The Heat Index (HI), or the "Apparent Temperature", quantifies how the humidity of the air affects human comfort and the stress that the combination of heat and humidity puts on the human body. The HI is intended to provide a sense of what the air temperature "feels like" when humidity is taken into account.
- Heat Wave: The National Weather Service defines a heat wave as a period of at least three days when the temperature reaches 90F or higher.