The storm system tore from eastern Nebraska across Iowa and parts of Wisconsin and Illinois, leaving behind a swath of destruction over its nearly 800-mile trek. A woman in Indiana was found dead clutching her grandson in her crushed mobile home while another person was killed in Iowa.
"Impressive satellite image of the crop damage from yesterday's storms showing 2 distinct damage swaths," the NWS tweeted.
When the system reached Des Moines, forecasters said wind gusts were clocked at more than 100 mph. That caused devastation across farm communities.
A highlighted area shows where some of the swaths of damage to farmlands were located, spanning in a line from west to east.
"Over time will become more easily visible as crops wilt/die," the NWS said. "Also likely to see extent widen as crops on the fringes may give in to damage they sustained."
Forecasters said that the damage swath was also spotted on GeoColor imagery from the GOES-East satellite.
Iowa Gov. Kim Reynolds said Tuesday early estimates indicate 10 million acres have been damaged in the nation’s top corn-producing state and many grain bins were destroyed. That's nearly a third of the roughly 31 million acres of land farmed in the state sustained damage from the derecho.
The most significant damage is to the corn crop, which is in the advanced stages of development, nearly a month away from the beginning of harvest.
Iowa Agriculture Secretary Mike Naig said tens of millions of bushels worth of commercial grain storage and millions of bushels of on-farm grain storage have been damaged or destroyed.
“It’s incredibly devastating to see what’s happening to crops, and to structures all across the storm path,” he told reporters.
Utility officials in Iowa said it will likely take several days to restore power to everyone.
According to the National Oceanic and Atmospheric Administration's (NOAA) National Severe Storms Laboratory (NSSL), a derecho is a widespread, long-lived wind storm that is associated with a band of rapidly moving showers or thunderstorms.
"Although a derecho can produce destruction similar to that of tornadoes, the damage typically is directed in one direction along a relatively straight swath," the NSSL states. "As a result, the term 'straight-line wind damage' sometimes is used to describe derecho damage."
In order for a cluster of thunderstorms to be defined as a derecho, a wind damage swath must extend for more than 240 miles and include wind gusts of at least 58 mph along most of its length.
The Associated Press contributed to this report.