On June 28, if anyone in the greater Washington D.C. area ran a weather-modeling service called Deep Thunder, they would have known a derecho windstorm was about to rip trees from the ground, knock out power and leave millions of people stifling in relentlessly sticky heat.
No one did.
As a result, millions of people suffered for days on end as utilities scrambled to restore electricity. Many businesses were idled through the Fourth of July holiday. Untold millions in wages and revenue were lost. At least 13 people died.