Why are there floods in Phoenix, Arizona?

Question

This is for a geology class, so i need real, intelligent answers. Explain why there are floods in a desert area and what kind of dammage occurs. Thank you!

Answer 1

Phoenix lies in the middle of a harsh, arid, desert climate. Rainfall is little and precipitation events (such as thunderstorms) occur rarely. When they do, however, you get an extremely high volume of water dumped in a very short period of time. As a result, existing water tributaries and streambeds cannot hold the excess water causing sudden, catostrophic floods to occur. These floods may cause serious damage to buildings and infrastructure (such as streets, electical lines, and sewers). Not only that, but these flash floods are usually underestimated by local inhabitants who attempt to drive through water surges and, in the process, cause themselves bodily harm and contribute to more structural damage.

Answer 2

If you have ever lived in Phoenix, Glendale, Peoria, or even many other cities in Arizona, during the Monsoon, you would realize that there is NO SHORTAGE of Electrical storms/ thunderstorms.
So that is somewhat untrue.
However, the rest of that previous answer is very true.
The Phoenix area receives like 4 inches or less ( I think thats right) per yr. .
but some of the monsoonal storms bring or dump sooo much all at once that the canals, man-made or otherwise, are overloaded. The Desert sand is different than beach sands, which readily absorb water...the desert is so dry, that the rains just run across the top of the sand, pretty much.
And it is quite flat right in the city, so the water runs down the storm drains, or canals from the deserts, and enters the city and has no place to go, thus flooding much, and yes sometimes causing alot of damage to various structures.
I want to go back to the desert.
I miss the Monsoonal rains, they come around the middle to the end of June.
It goes from 110 or 120 degrees F. right down to a nice cool, well, sorta Muggy 90 degrees. AHHH. Or less, where you can even shut off the A.C. for an hour or so it gets so cool. Like *0.
I missed WA state when I was in AZ. but now back home for five yrs. I miss the desert. I lived in Peoria/ Glendale for 5 yrs.
About 15 mi. S.E. of Phoenix.
I think that is right.
Good luck with your report.
DJH


They do have a pretty good system now for flood control.
I miss the desert storms.

Answer 3

Primarily because the ground in a desert area is very dry and hard, meaning that it does not easily absorb water. In an area with softer ground, much of the moisture from a rainstrom would be absorbed quickly into the ground. In the desert, the same amount of rain can cause flooding because the ground cannot absorb the water fast enough. Arizona in particular gets really odd storms where it rains VERY heavy for about 15-30 minutes then stops, so a large influx of water all at once on hard ground.

The main reason you heard about floods in Phoenix and surrounding areas though is human stupidity. People here actually build homes and roads too near (or even INSIDE) the riverbeds and washes. Most of the year, the rivers and washes are dry, then when there is a storm they fill up with river quickly (ie, flash flood). People who are used to driving through the washes still try too. Years back (in the 70's) people would actually build inside the Salt River bed and every year act surprised that water came and washed them away.

Another major cause of flooding problems in the Phoenix Metro area is lack of proper planning by City Planners. We have little to no drainage in most areas of the City. During a big rain storm, several roadways, like those around North 23rd Ave, will fill up to reach car windows and are strong enough in current to wash smaller cars down the road. City planners didn't plan for storm drainage because Phoenix is a desert. Most areas will have one strom drain at each one mile stretch which causes the strong currents from water rushing to those drains.

Answer 4

I agree with the other two answers, with one major addition. The Salt River drains hundreds of square miles of mountains, which get significantly more rain than Phoenix does. It can be hot and dry in Phoenix yet raining cats and dogs up in the mountains. When all this water accumulates it causes a flash flood, which typically is a wall of water rushing down the normally dry Salt River bed. This water has a lot of force behind it, and can bring huge boulders with it or sweep cars away. Erosive effects of this water can damage buildings other infrastructure.