SAFETY, HEALTH AND ECONOMIC IMPACTS OF WEATHER AND CLIMATE IN THE URBAN ENVIRONMENT Raymond J. Ban The 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 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 Wave July 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 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

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.