SAFETY, HEALTH AND ECONOMIC IMPACTS OF WEATHER AND CLIMATE IN THE URBAN ENVIRONMENT Raymond J. Ban The Weather Channel, Inc.
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SAFETY, HEALTH AND ECONOMIC IMPACTS OF WEATHER AND CLIMATE IN THE URBAN ENVIRONMENT
Raymond J. BanThe Weather Channel, Inc.
MY MISSION TODAY
Provide an overview of certain weather/climate events that when occurring in urban environments produce unique challenges and impacts.
Selected Weather/Climate Events
• Winter Storm
• Heat Wave
• Flood
• Tropical Cyclone
• Wildfire
Urbanization results in:
- Increased threat for more damage and delays .
- Hundreds killed, tens of thousands injured in auto accidents.
- Millions marooned at home and work, disrupting commerce.
- Tremendous costs in road, rail and highway maintenance.
Implications for the forecaster:
– Small events (such as a dusting of snow or a light glaze) can have a huge over a short period of time – information must be collected and communicated rapidly.
– Large snow events can impact tens of millions of people for several days to a week or more
– forecast lead time is important for industry and emergency management.
– Icing can result in power outages affecting millions.
WINTER STORM
The Chicago heat wave of July 1995 caused somewhere between 465-739 deaths. It was exacerbated by the urban heat island which keeps night-time temps warmer.
Global Change Scenario:
– Very likely: More hot days.
– Very likely: Higher heat index.
– Likely: Higher night time temperatures.
– Likely: More heat waves.
HEAT WAVE
Chicago Heat WaveJuly 13-16, 1995
HIGH TEMP: 104° F (O’Hare)
DEW POINT: 75° TO 82°F
NIGHT-TIME TEMP: >75°U.S. WEATHER-RELATED DEATHS
AVERAGE PER YEAR (approx.)
Hurricanes 20
Tornadoes 60
Flooding 85
Lightning 70-100
HEAT WAVES 235
Heat waves are the #1 weather related killer and are likely to increase.
Urbanization results in:
- Reduced infiltration of rainfall.
- Accelerated runoff rates.
- Artificial flood-control channels with excessive rates of flow (where children sometimes play).
Implications for the forecaster:
- Reduced flash flood guidance values (lighter rain results in flooding).
- To have the desired warning lead time, sometimes must warn of flooding based upon rainfall in storms approaching area (before they arrive).
- In urban areas near mountains, must warn for rain falling over adjacent hills that will rush down streams and rivers (e.g., Las Vegas).
- Each new housing or business development changes the flood threshold and runoff characteristics of the urban watershed.
FLOOD
Urbanization results in: Implications for the forecaster:
– “Warning – Response” model is stressed.
– Increased difficulty in evacuation due to road constraints.
– A flood catastrophe to inland urban areas from a tropical storm or hurricane could be as costly as impacts at the coast (e.g. tropical storm Allison).
– Increased demand for safe shelters.
– More boats in the water make more people vulnerable to marine impacts.
TROPICAL CYCLONE
– Lead time
– Lead Time
– Lead Time
Urbanization results in:
- Increasingly expanding housing areas into hilly, wooded suburbs.
- Many communities in the West are in semi-arid environments, prone to long dry summer seasons and especially vulnerable to drought.
- Population growth outstripping water supply.
- Desire for trees near homes for shade and rural atmosphere as “escape” from the city.
Implications for the forecaster:
- Recognition of dangerous fire weather conditions is relatively easy.
- Prediction of in-fire weather conditions is VERY difficult.
- Scale of the wind phenomena usually smaller than observations or numerical models. Special mesoscale models now exist that integrate fires into models: e.g., Terry Clark, NCAR).
Urban Flooding
WILDFIRE
IN CLOSING….
TWC has large interest in this area.
70% of TWC viewing households are in urban environments.
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