How do floods start?

Answer

According to NOAA, most floods start with slow-moving thunderstorms, thunderstorms that travel the same path several days in a row, or hurricanes. Floating debris and ice sometimes form a temporary dam which causes the water to back up until the debris breaks free, releasing a wall of water and causing flooding downstream.

Some rivers flood seasonally with rains. Warm rains in mountain areas melt snow to increase the volume of water in the river. Hurricanes or tropical storms bring large amounts of rain inland and cause the flooding of streams and rivers.

Urbanization increases the flood potential. The covering of formerly grassy pastures with asphalt increases the runoff from two to six times. Urban flooding turns streets into rivers. A basement in an urban setting becomes a potential death trap due to flooding.

NOAA warns residents to know the flood dangers for where they live. Most floods occur with some warning, and it is important to evacuate on the recommendation of officials. Floodwaters of only 6 inches have the ability to knock a human off his feet. If the water is over 2 feet in depth, it will float an automobile. Each additional foot of water adds another 500 pounds of lateral force to move the vehicle downstream.

Reference:
Q&A Related to "How do floods start?"
The smallest tributaries are the first to overflow their banks. Swollen streams and creeks feed into rivers and if too many tributaries within a watershed carry too much water, river
http://www.ehow.com/facts_7433377_flood-starts.htm...
Excess water, usually from a heavy rainstorm, and, what most people don't realize is; bridges aren't high enough from the water line so the water hits the bridge and travels sideways
http://wiki.answers.com/Q/How_did_floods_start
Driving traffic to porn sites is against Google+'s policies,[1] so pornographers (that's a word, right?) will have to be very careful about what they are doing. Facebook and many
http://www.quora.com/When-the-Google+-flood-gates-...
Flooding is caused by too much gas applied at the wrong time and can prevent a saw from starting. Flooding is the major cause of a stalled chainsaw engine. As previously instructed,
http://forestry.about.com/od/chainsaws/ss/start_cs...
Explore this Topic
if your leaf blower won't start, there are a few things you should check. First check for fuel or spark plug problems. To do this check for a flooded engine, and ...
About -  Privacy -  Careers -  Ask Blog -  Mobile -  Help -  Feedback  -  Sitemap  © 2014 Ask.com