hen it snows or rains, some of the water is captured in the dirt.  Plants might absorb some water, some evaporates, and what is left, goes to streams.  This is called runoff.  Floods happen when dirt and plants do not absorb the water.  Then the water flows in amounts that cannot be held in streams, ponds, and constructed reservoirs.  Out of all the precipitation, about 30 percent is run off.  With large amounts of melting snow, it may be even more.  Some floods that overflow riverbanks form a flood plain.  A flood that rises and falls quickly with little or no warning is called a flash flood.  Intense rainfall over a small area usually causes flash floods.  Methods to protect areas from floods are dams, reservoirs, floodways, and levees. 

here is electricity in clouds.  There are small water droplets or ice crystals that carry electricity.  There are millions and billions of droplets and ice crystals and the amount of electricity gets bigger and bigger.  When the quantity of electricity reaches a critical amount, it jumps from the top of the cloud to the bottom.  That electricity is lightning.  It also makes a loud sound known as thunder.  Whatever you do, do not go near a tree or go in water during a thunderstorm!  Lightning is attracted to water and trees.  The safest thing to do is stay in a car because the tires are insulators or stay in a house with a lightning rod on top.  You should also unplug electrical appliances.  Power surges from electrical storms can cause damage to the appliances.