Violent tornadoes strike Nebraska, Iowa amid threat for more Saturday

Thunderstorms spawned numerous tornadoes across the Plains Friday, some of which turned violent and destructive in Nebraska and Iowa.

Why it matters: The storms, forecast to be spread across several states, reserved their fury for just two, in an outbreak without a recent precedent.

• The National Weather Service issued at least four tornado emergencies, its most dire type of tornado alert, indicating an imminent threat of potentially catastrophic damage in a populated area.

Threat level: Powerful tornadoes hit near Lincoln and Omaha, Nebraska Friday afternoon.

• The storms are part of a larger, slow-moving weather system that is forecast to bring severe weather, including potentially strong tornadoes, to a vast region from the Texas border with Mexico into the Midwest on Saturday.
• On Friday, social media footage from storm chasers showed wide tornadoes striking communities on the western side of Omaha, Neb., causing major damage.

The latest: Elkhorn, situated about 15 miles west of the center of Omaha, was particularly hard hit, though no fatalities were reported.

• “Many houses are flattened and many houses also have significant damage,” Omaha Fire Chief Kathy Bossman said, according to KOLN-TV.

Between the lines: At one point, Omaha had a tornado warning for downtown, a tornado on the ground to its north and another tornado on the ground just to the southeast of the city, all viewed by both weather spotters and Doppler radar.

• One tornado touched down near Omaha’s Eppley Airport, with footage shot by a passenger on a jet waiting on the tarmac.
• It was an unusual clustering of tornadic thunderstorms in a relatively small region, owing to the ideal conditions for these storms to form.
• The tornado that hit Elkhorn and then moved to the northeast showed debris lofted to about 25,000 feet above the surface along with radar-observed surface winds consistent with a tornado rated above an EF-4 or greater tornado.

Zoom in: Damaging tornadoes also struck Iowa, including Minden and Harlan.

• “You are in a life-threatening situation. Flying debris may be deadly to those caught without shelter,” read the tornado emergency language for Harlan, Iowa, issued at 5:49pm CT.
• “Mobile homes will be destroyed. Considerable damage to homes, businesses, and vehicles is likely and complete destruction is possible.”
• The NWS forecast office in Omaha issued at least 40 tornado warnings during this event, as storms erupted throughout its forecast region.

What’s next: The National Weather Service notes heightened concern on Saturday for a “widespread” outbreak of severe weather, potentially including powerful tornadoes, across an area much larger than was seen Friday night.

• The severe thunderstorm outbreak will affect tens of millions and multiple cities, including Oklahoma City, Wichita, Des Moines, Kansas City, Dallas and Omaha all the way to Madison, Wis.
• Moisture-rich air flowing northward from the warmer-than-average Gulf of Mexico, combined with slow-moving thunderstorms could yield significant flash flooding as well, particularly in parts of Oklahoma on Saturday.

Go deeper: Severe storms, some with “strong tornadoes,” threaten more than 60 million