A deadly week-long heat wave has killed at least 30 people in the US, and at least 144 people died in flash floods in Russia. Flood warnings also have been posted in Britain.
"This is becoming a black swan of heat waves, in the sense that it's such a long heat wave, such a severe heat wave and encompassing such a large area," according to Chris Vaccaro, spokesman for the National Oceanic and Atmospheric Administration.
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