About 16 minutes before the tunnel formed, a tornado warning was issued for people in and around Moore, Oklahoma.
According to the National Weather Service, the average lead-time for a tornado is 13 minutes. Sioux Falls Emergency Manager Regan Smith says the City tries to make sure citizens get as much warning as possible.
"We put a person, typically myself, at the weather service when there is severe weather going on. So, we can work with the weather service in getting those warnings out. Whether it's through the weather radios, the outdoor warning sirens and then obviously our relationships and partnerships with the media," Smith said.
Smith says city officials are as prepared as they can be for a disaster like Oklahoma's.
"On a scale that big you're not going to have enough resources to deal with everything immediately. But you do have the structure to handle it and assess the situation and then coordinate all the resources that are coming in to assist you," Smith said.
There are also preparations you can take before disasters strike.
"Definitely in your home, school, workplace pre-identify where you're going to shelter when the storm does hit or when that warning is issued." Smith said.
Smith says the most important thing people can do is to always be aware of their surroundings.
"Pay attention when their making their plans. Whether it's camping or sporting events. Those type of things if they're going to be outdoors. But when they are home to just keep an eye at the sky," Smith said.
You can help Oklahoma relief efforts by visiting redcross.org, dialing 1-800-REDCROSS or texting REDCROSS to 90999 to make a $10 donation.