How Blackouts during Heat Waves Amplify Mortality and Morbidity Risk

Used in 2 entries

For each citing entry, the verbatim excerpt and Likelier's calculation notes (how the source's number was converted to the lifetime-probability framing) are shown below. Click through to read the full claim ledger.

1. [1] Extreme heat Risk

   Statistic

   A concurrent multiday blackout during heat-wave conditions more than doubles the estimated rate of heat-related mortality across Atlanta, Detroit, and Phoenix; Phoenix showed by far the largest amplification.

   “"We find the concurrence of a multiday blackout event with heat wave conditions to more than double the estimated rate of heat-related mortality across all three cities."”

   Calculation notes

   Supports the "multiday power outage during a heat wave" personal factor multiplier of 2 (≥2× from "more than double"). Modeling study of compound heat-plus-grid-failure events in three US cities; the factor is the cross-city floor, not the Phoenix-specific worst case. Also underpins the post-storm-heat caveat (Hurricane Beryl, 2024). Does not affect the headline global lifetime figure.
   

   Independence note: Stone et al. is a primary modeling study (3HEAT / Three-City Heat and Electrical Grid Failure Adaptation Study) on compound infrastructure-climate hazards, independent of the WHO, Zhao, and JAMA mortality-trend sources.

   Source date: 2023-05-24 · Accessed: 2026-06-14

2. [2] Post-hurricane heat death Risk

   Statistic

   A combined heat wave and blackout multiplies heat mortality roughly 2x in Detroit/Atlanta and ~7x (about 700%) in Phoenix vs. heat alone

   “more than 50% of the population”

   Calculation notes

   Provides the mechanism and the upper-tail scale: a prolonged blackout during a severe heat wave can multiply heat mortality several-fold to (in Phoenix) ~700%. Used to justify the wide upper bound (5e-4) of the uncertainty band, since Beryl was a mild heat coincidence. Excerpt is the verbatim Phoenix morbidity figure (share of population needing emergency care).

   Independence note: Independent Georgia Tech / University of Michigan modeling team.

   Source date: 2023-05-22 · Accessed: 2026-06-13

Also cited in these entries

NaturalDirect

Extreme heat

What are the odds of dying from extreme heat?

1 in 333 lifetime(0.3%)global

Natural

Post-hurricane heat death

How likely is dying from heat after a hurricane knocks out your power in summer?

1 in 20,000 lifetime(0.005%)subgroup