26 votes
Accepted

With all the rain Seattle gets, why is widespread flooding relatively rare?

Regarding climate, it does not rain in Seattle as much as people think; Seattle is in the snow shadow of the Olympic Mountains. It doesn't rain much in summer at all. Seattle gets rather dry in July ...
David Hammen's user avatar
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19 votes

With all the rain Seattle gets, why is widespread flooding relatively rare?

Catastrophic flash flooding is usually a sign of poor city/road planning in flat areas or due to torrential downfall of rain. The reality is that all the terrain in Washington allows water to drain, ...
f.thorpe's user avatar
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14 votes

Could a massive flood have formed the Grand Canyon?

tl;dr: no. Long answer: First of all, like mentioned by others in the comments, you would need some physical mechanism to take a whole lot of water, evaporate it, and drop it at once at a place ...
Gimelist's user avatar
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8 votes
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Could a massive flood have formed the Grand Canyon?

In addition to all of the above there are meanders inn the Grand Canyon which are hydraulic outcomes of 'minimum energy flow configurations'. This constrains the discharge rates that are possible - to ...
Gordon Stanger's user avatar
7 votes
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Is there a quick way to roughly estimate how quickly a flood will move downstream?

My first thought would be to use Manning equation as an approximation. It does not take into account the effect of a dam burst providing excess water and immediate flooding, although for larger scales ...
Rob's user avatar
  • 751
7 votes

What is the difference between a flood and a mudslide?

A flood occurs when land that is normally dry is covered by water. The source of the flood water is generally from bodies of water, such as: rivers, lakes, dams and even the ocean. Rivers can flood, ...
Fred's user avatar
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7 votes

Is it possible for a local flood to reach the heights of a mountain, say 7000 ft, and wash away a ship over 350 miles?

No it isn't possible. 7000 feet is 2133 metres. That water level would cover almost all the land mass of the globe, except for the highest mountains, like the Himalayas, the Andes etc. It would need ...
Andy M's user avatar
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7 votes

With all the rain Seattle gets, why is widespread flooding relatively rare?

We do get flooding in the Puget Sound lowlands, but it actually happens most often when a mid-winter warm front brings a moderate amount of rain to higher elevations, causing sudden, extensive ...
juliaseid's user avatar
6 votes
Accepted

Why was the flooding in Derna, Libya so catastrophic?

I hesitate to write this answer as I am neither a metereologist, nor a hydrologist, nor a civil engineer with expertise in dams. From what I gather from news reports and available data, the proximate ...
njuffa's user avatar
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5 votes
Accepted

How was Venice flooded?

If the winds subsided and the flooding was caused purely by tidal effects, which are astronomical events, shouldn't it have been predictable months, if not years in advance? The tides are only ...
David Hammen's user avatar
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5 votes

How was Venice flooded?

Venice can't really be flooded by rivers, since there are none worth mentioning throughout the city. High tides are predictable, yes. Take a look at how Venice is situated. The historic city is ...
Erik's user avatar
  • 756
5 votes

With all the rain Seattle gets, why is widespread flooding relatively rare?

To add some concrete data to some of the great answers already here: Seattle is actually not particularly rainy, especially compared to other parts of WA, but also compared to other cities in the US. ...
stef's user avatar
  • 51
4 votes

What is the difference between waterlogging and flooding?

Waterlogging is a situation were soil is either fully or near saturated most of the time, the air phase is restricted and aerobic conditions prevail. Waterlogged soil may appear dry on the surface. ...
Fred's user avatar
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4 votes

With all the rain Seattle gets, why is widespread flooding relatively rare?

Because soil drainage would be higher and the ground would take long to saturate Floods don't always happen in Rainy weather all the time because first the soil needs to be saturated (the point where ...
Tardy's user avatar
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4 votes

Is it certain that hundred year floods have finite variance?

I'm sure a statistics guru over on cross-validated could answer this better for you, but here's some general info on estimating flood frequency fyi. The 100 year flood has a 1% probability of ...
rivercfd's user avatar
3 votes

How can flood inundation vary at the same river stage?

Hydrology major here, for whatever that's worth :) Some possibilities from my readings/internships: First I'd check the gage you're using for stage--if it's moved in the last 8 years, the stage may ...
DataWrangler's user avatar
3 votes

What was the storm surge height from Hurricane Harvey?

For a general view of the surge in the region, the maps in u-surge give a pretty good idea of numbers and more affected regions. The USGS provides a comprehensive view of High Water Marks (HWM) in ...
arkaia's user avatar
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3 votes

What is the potential impact of hurricane intensification and sea level rise on coastal flooding?

As you noted, the (predictions about) impacts of global climate change are region specific. The general reasoning behind predictions for many regions are similar however, as are some noteworthy bottom ...
cr0's user avatar
  • 1,178
3 votes

Is there a relationship between pressure drop and sea level rise?

Is there really a relationship between pressure drop and sea level rise? The author of the card was writing about storms at sea. By way of analogy, think of what happens when a person with a ...
David Hammen's user avatar
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3 votes

How to simulate rainfall for a 1 in 100 year storm event?

Sounds a bit unfeasible to me to really and truly properly simulate... a bit like asking the timeline of how a hypothetical 100 story building would be built. There's certainly some patterns to how ...
JeopardyTempest's user avatar
2 votes
Accepted

How to curb losses during annual heavy rainfalls

Flood control measures largely depend on: The amount of money available to create flood control measures The availability of raw materials that could be used to create such measures The locality of ...
Fred's user avatar
  • 24.7k
2 votes

Soil moisture conditions and air temperatures - literature needed

If you're after "basic" academic work, I suggest the following 2003 textbook from the Utah State University entitled, "Rainfall Runoff Processes", chapter 2: Runoff Generation Mechanisms It looks ...
Knob Scratcher's user avatar
2 votes
Accepted

What was the storm surge height from Hurricane Harvey?

My house elevation is 9.1 feet above sea level, according to all "expert" measurements. That includes the city, county, state, Feds, and all insurers. It seems about right to me. But then again, I ...
Serge's user avatar
  • 44
1 vote

Time of concentration - Difference between large and small basins

Unless you're needing specific methods for application purposes, the justification you're providing is clear and wouldn't require a citation. Maybe this is a homework question? Some rambling ...
Mortsde's user avatar
  • 41
1 vote

Time of concentration - Difference between large and small basins

This is a difficult question since time of concentration ($t_c$) can in theory, vary substantially, for two basins of equal size. Off the top of my head, I can imagine several other variables that ...
Z W's user avatar
  • 432
1 vote

Could a massive flood have formed the Grand Canyon?

There is evidence that at least part of the erosion in the Grand Canyon was caused by an outflow flood caused by the failure of a lava dam. https://www.gcrg.org/bqr/18-1/lava.html There is ...
Rob Grier's user avatar

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