There have been more than two dozen reported tornadoes in three states amid a twister outbreak in the Plains on Friday.
Twenty million Americans, from Texas to Iowa, are on alert Friday for tornadoes, large hail and damaging winds, as severe weather is expected to impact the Heartland into the weekend.
The highest tornado threat exists from the Dallas region north to Des Moines, Iowa.
There have been at least 25 reported tornadoes in Nebraska, Texas and Kansas so far on Friday, with some damage reported in northeast Texas and central Nebraska.
Tornado watches are in effect for parts of six states -- Iowa, Nebraska, Kansas, Missouri, Oklahoma and Texas, including Dallas -- into Friday afternoon and evening.
The National Weather Service in Omaha issued a tornado emergency for parts of east-central Nebraska Friday afternoon after a confirmed "large and destructive" tornado was seen over Elkhorn, Nebraska.
Two particularly dangerous situation tornado warnings were also in effect in Nebraska near Omaha and near Norfolk.
In Omaha, several houses were destroyed and at least two people have been transported with minor injuries in the storm, police said. Eppley Airfield also saw some damage to private planes, authorities said.
"We've been very fortunate with very few injuries," Omaha Police Chief Todd Schmaderer told reporters during a press briefing Friday. "It seems like our warning systems in the city of Omaha have been very effective."
Three people were injured after a reported tornado severely damaged a building in Lancaster County, Nebraska, authorities said. The incident was reported around 3 p.m. CT. Friday at Garner Industries in Lincoln, the Lancaster County Sheriff's Office said. Approximately 70 people were inside the building when the reported tornado struck, with three transported to area hospitals in non-life-threatening condition, the sheriff's office said.
MORE: How to shelter during a tornado if you don't have a basementOn Saturday, some of these severe storms could stretch as far north as Chicago; Milwaukee; Green Bay, Wisconsin; and Traverse City, Michigan. These areas will mostly see damaging winds and some hail.
The severe thunderstorms could also produce very heavy rain causing flash flooding, with the highest flash flood threat in Oklahoma, including Oklahoma City and Tulsa, and extending into northern Texas and eastern Kansas. Up to half a foot of rain is possible locally in a short amount of time.
The highest tornado threat on Saturday is across the Plains from Texas to Iowa -- including Oklahoma City; Kansas City, Missouri; Wichita, Kansas; and Des Moines -- in the afternoon and evening.
The tornado threat will decrease but not dissipate on Sunday, with storms expected to redevelop from Texas to Missouri to Illinois in the afternoon and evening. Severe weather with damaging winds, hail and an isolated tornado are possible in cities including St. Louis and Little Rock.
The flash flood threat will also move into Arkansas, including Little Rock, on Sunday.
MORE: 3 life-saving tactics to use if in a car during a flash floodThe current tornado threat comes after Thursday saw four reported landspouts and tornadoes in four states -- Kansas, Colorado, Wyoming and Utah, primarily in rural areas. Parts of Kansas also saw hail larger than a baseball and winds gusting up to 70 mph.