No matter what the disaster, there are some human reactions that can be predicted such as anxiety, sadness, depression and anger.
These reactions are so common that many people know to look for signs of them after experiencing a trauma. But it's just as common for victims to suppress these emotions for weeks, months or even years.
Dr. Gerard Jacobs directs the Disaster Mental Health Institute at the University of South Dakota. He said after a disaster people can get caught up in the rush of clean up work which often delays their ability to process what happened to them.
"People may function very well in the initial stages of the event," he said. "But then once they're through with the pressure, they start to let their defenses down and the psychological reactions then can just kind of overwhelm their coping skills."
In addition to emotional problems, victims may also develop cognitive lapses. Jacobs said it's common to lose the ability to focus or concentrate. Behavior can also change. He said some people may become over-protective of family members or they may isolate themselves from everyone.
Physical ailments can develop too.
"We see a lot of gastrointestinal problems with nausea and things like that, general disturbances of the gastrointestinal system, difficulties with sleep, elevated heart rate, elevated blood sugar, elevated blood pressure," he said.
Jacobs said often the cure for these problems is to simply talk about the situation that caused them. And in his experience many victims are more than willing to share how they're feeling if given the opportunity. He said that is especially true for young children who rely on adults for reassurance.
Kay Bochert is a counselor with the Red Cross Mental Health Stress Group. She has been spending a lot of time with children in Hugo the past few days.
She said one of her cases involved a 5-year-old boy who witnessed the tornado tearing up his neighborhood. His mother told Bochert that her son was having a hard time coping with the situation.
"He had two dogs and a cat and they had to find a place for the two dogs and the cat and that was really important for him," she said. "His mother reassured him several times that they were okay and they were being fed and there wasn't anything wrong with him."
Bochert said she spent half an hour with the little boy and just let him talk about his pets and anything else that was on his mind. By the end of the conversation she says he was talking excitedly about the impending arrival of his new baby sister. She said that was a good sign.
Bochert has also visited Oneka Elementary School in Hugo. School officials brought in counselors from throughout the district this week to talk with students about the tornado.
Bochert said she and the other counselors met children as they got off the bus. Some of the kids were crying and many were also worried about lost pets. But she said for the most part the children seemed to be coping well.
"With young children they will want to talk about it right away," she said. "And the best thing to do would be to just let them talk and let them cry and really let them do anything they need to do in order to get the emotion out. The worst thing we can do is make them be quiet."
Bochert said the Red Cross and the school are discussing whether they should continue to offer counseling to Hugo students during the summer, since school will only be in session for two more weeks.