Talk:Flash flood

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Is a flash flood due to accumulation? - Lasaraleen

"More people die yearly in floods (127 on average) than by lightning (73), tornadoes (65), or hurricanes (16)." Is this just a U.S. figure? If so it should be labeled as such. It seems mighty low for worldwide. - Ace of Sevens

Also, it should be stated what year those figures are for. Populations numbers change, etc.

~ender 2005-07-22 15:44:MST

[edit] It is not just a US phenomenon!

Peter Shearan 14:50, 20 August 2006 (UTC)

Who said it was? I don't think it makes a lot of sense to have a section for each country, though. I'll update the article. -- Moondigger 15:15, 20 August 2006 (UTC)

[edit] How Long does it take?

Thank you to whomever changed the caption to remove the reference to millions of years to carve Antelope Canyon. My take is that it is in the time range of 10,000 years, but I don't REALLY have a source that is quite so specific. So, thank you for making it unspecified, which I think is fairest. Ratagonia 06:14, 8 November 2006 (UTC)

It's not a matter of "fair." It's a matter of accuracy, and "millions of years" is correct. I'm changing it back. -- Moondigger 16:47, 8 November 2006 (UTC)

You have a source? Please state it. A source for circa 10,000 years: Ranney, Wayne. Carving the Grand Canyon.Grand Canyon Association, 2005. Grand Canyon AZ. ISBN: 0-938216-82-1 Ratagonia 06:54, 9 November 2006 (UTC)

1. The caption refers to Antelope Canyon, a slot canyon near Page, Arizona -- not the Grand Canyon, which is what your reference addresses.

2. Taking up your reference anyway -- most geological references I have read indicate the Grand Canyon formed over the course of millions of years. The idea that it was "carved" in 10,000 years is generally supported only by young-earth creationist literature. I do not know if Wayne Ranney is a YEC, and will not waste the time doing the research. However I will say that his theory is at odds with the vast majority of geological literature about canyon formation.

3. My Antelope Canyon-specific source is the Navajo tour guide who explained the history of the canyon when I toured there in 2005.

4. A simple google search turns up a few references indicating "millions of years" as a rough estimate of the time it takes for slot canyon formation. Even if such references were off by an order of magnitude (hypothetically speaking -- there's no credible evidence that it's off), it would still be "hundreds of thousands" of years, not "10,000."

5. The Wikipedia article for "slot canyon" specifies an even longer estimate of "100-200 million years" for slot canyon formation. That estimate was not written by me.

Comment: Per #4, if this estimate (100-200 million years) is off by two orders of magnitude, the caption would still be accurate as "millions of years," -- it would have to be off by three orders of magnitude before we would be forced to change the caption to "hundreds of thousands" of years.

-- Moondigger 15:36, 13 November 2006 (UTC)

Please see WP:RS. If you can come up with a reliable source, please do so. So far - none. I also cannot find a source that indicates on the order of 100,000 years, so will not put that in either. But:

If you'd like, we can discuss it, but this falls into the realm of original research, rather than a citable source. Mr. Ranney is a staff geologist with the GCNHA, not a Young Earth Conjecturist. Your Antelope Canyon tour guide is not a citable source. The Wikipedia article on slot canyons is not a citable source.

For the two terms I was a geophysics major, this was the kind of things we figured out. What is the erosion rate in antelope canyon? How deep is it? How big is it? For it to be millions of years old, the erosion rate would have to be laughably small. It is a small feature. There may have been canyons like it in the area 1 million years ago, but it is implausible that the feature we call Antelope Canyon today was at all similar to what it is today.

190 million years ago, this area (the Colorado Plateau) was a vast basin west of a very high mountain range, slowly filling with sand which became the Navajo Sandstone. After that, the Navajo was buried by more sediments, pushed down into the earth and cooked, etc. etc. While geological changes take place over vast times, even on a geologic timescale, hundreds of millions of years is a long time. Small (100's of meters) features like Antelope Canyon and other slot canyons are transitory features. Etc. Ratagonia 00:11, 8 January 2007 (UTC)

I'm fine with not stating any estimated timeframe, given the lack of citable sources. I do object to very short estimates such as 10,000 or 100,000 years, especially when the source you cited doesn't address Antelope Canyon in the first place. As I said before, I do not know or care if Wayne Ranney is a YEC; his 10,000 year estimate for the formation of the Grand Canyon is orders of magnitude shorter than any other citable reference I have found, and only matches within a single order of magnitude the theories of Young Earthers. -- Moondigger 22:14, 31 January 2007 (UTC)

One more comment, though. "Millions of years" is not an unreasonable estimate. It covers the entire range from one million to one billion years, and at least gives an idea that such formations are not built in a very short timeframe. Ten thousand years is laughably short on a geologic timescale, especially since the primary weathering agents in Antelope Canyon are water and water-driven sand. Rainfall is scarce in that area of Arizona and Utah and has been scarce for geologically long periods of time. One could reasonably argue that the Grand Canyon formed faster than Antelope Canyon because it had the Colorado River to act as a constant weathering agent, whereas Antelope Canyon gets enough rainfall to cause a flood only very rarely. - Moondigger 22:23, 31 January 2007 (UTC)