The cause of the dust bowl is a little complicated. The plains were covered with thick green grass that held sod into place. In the years before World War I, the fields were plowed setting up the dust bowl. Then in the 1930's a severe drought hit the plowed areas scattering sod and dust everywhere. Thus the dust bowl.
The effect of the dust bowl is even simpler. Because of no rain, farmers had to deal with farming without rain. There crops would rot and die. They now had no income for their familles in this time of need. The farm animals would suffocate from all of the dust. Even humans died from inhaling the dust too much. Food was hard to eat because so much dust would scatter throughout the household. All in all, the effect of the dust bowl caused havoc everywhere the dust touched.