May 23, 2011 -- A series of devastating storms ripped through several Midwestern states over the weekend, including a monstrous tornado that killed at least 89 people in Joplin, Mo..
As rescue workers continued to search for victims Monday morning, many said they could hear trapped survivors crying out for help.
Here are tips you can follow to stay safe before, during and after a fierce storm.
Tornadoes 101: Before the Storm
Tornadoes are quick-moving, fierce storms that can strike with little or no warning, and can change direction at any moment.
Know the difference between a tornado watch and a tornado warning: A tornado watch means weather conditions are right for a tornado to form in your area, whereas a tornado warning means a tornado has been sighted and may be headed your way.
Pay Attention to Warnings
When the National Weather Service sends out tornado alerts or warnings, tune to NWS radio. The station is dedicated to giving 24/7 updates on current weather conditions. Your local radio and TV stations will also announce NWS alerts.
Even if a tornado watch is issued for your area, stay inside and be aware of changing weather conditions.
Visit the National Oceanic and Atmospheric Administration's website to track the country's most dangerous storms.
Watch the Skies
Sometimes it's as simple as looking out your window. FEMA advises that as long as the storm hasn't already hit, check the sky for the following danger signs:
Dark, often green sky
Large, dark, low-lying cloud (particularly if rotating)
Strong wind that sound like a loud roar. It's often been described as similar to a freight train
Tornadoes 101: During the Storm
What you should do during a tornado could change depending on where you are. Nonetheless the Red Cross suggests having a family preparedness plan head of time so everyone knows what to do when a storm hits and where to meet.
If you're in a structure with sturdy walls, you should go to any pre-designated shelter if there is one, like a storm cellar or basement. If there is no pre-designed shelter, head to the lowest floor of the building and find the most central room. Be sure to stay away from windows, doors and outside walls.
If you're in a vehicle or mobile home, FEMA recommends getting out immediately and heading for a more secure building or storm shelter.
"Mobile homes, even if tied down, offer little protection from tornadoes," FEMA says on its website.
If you're outside and there's no shelter available, get as low as you can. Head for a ditch or land depression and cover your head, FEMA recommends. Do not go under a bridge or overpass.
One thing FEMA says not to do that could be a natural instinct for most: Do not try to outrun the twister if you're in a congested or urban area.
"Instead, leave the vehicle immediately for safe shelter."
Keep an eye out for flying debris.
Tornadoes 101: After the Storm
The aftermath of a tornado can be devastating, but it's important to take all the necessary safety precautions even when the storm is over.
The Center for Disease Control and Prevention (CDC) recommends that you check yourself and family members for injuries and seek medical attention immediately, if necessary. Apply pressure to any bleeding wounds.
If you or someone you know is trapped or severely injured, the CDC says try not to move them unless there is immediate danger, but seek medical assistance immediately. Use thick gloves when handling or moving fallen debris, but watch for glass and exposed nails.
Stay away from downed power lines and be careful when walking around or through any damaged structures that might be unstable.
ABC News' Leezel Tanglao and Lee Ferran contributed to this report