Jefferson County - East-West Gateway Coordinating Council

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HAZARD: Heat Wave
JEFFERSON COUNTY HAZARD PROFILE WORKSHEET
POTENTIAL MAGNITUDE (Percentage of jurisdiction that can be affected):
_ Catastrophic: More than 50%
X Critical: 25% to 50%
_ Limited: 10 to 25%
_ Negligible: Less than 10%
Jefferson County – Section 2
FREQUENCY OF OCCURRENCE:
_ Highly Likely: Near 100% probability in next year
X Likely: Between 10 and 100% probability in next year, or at least one chance in 10
years
_ Possible: Between 1 and 10% probability in next year or at least one chance in next
100 years.
_ Unlikely: Less than 1% probability in next 100 years
SEASONAL PATTERN:
Heat waves typically occur in the summer months of June, July and August.
AREAS LIKELY TO BE AFFECTED MOST (BY SECTOR):
Every sector of the entire planning region will be affected by a heat wave.
PROBABLE DURATION:
Heat wave occurrences have been known to last approximately one month.
POTENTIAL SPEED OF ONSET
(Probable amount of warning time)
_ Minimal (or no) warning
_ 6 to 12 hours warning
X 12 to 24 hours warning
_ More than 24 hours warning
EXISTING WARNING SYSTEMS: National Weather Service
COMPLETE VULNERABILITY ANALYSIS:
The EWGCC region is extremely vulnerable to heat wave hazard based upon the summer
weather characteristics; St. Louis has been included in the top five cities in the U.S. for
having the largest number of heat related deaths. Based on regional heat wave statistics,
the county could represent 5% of those damages. In the developed portion of the county,
it was estimated that approximately 2,100 persons and 500 buildings valued at $49 million