Talk:Corfu Slide

Ice in the Corfu Slide?
Interesting discussion from talk pages shared here.

Corfu slide
Hi there! I like the stuff you've added to the article, I haven't been able to get a picture yet but hope to soon. Just as a matter of interest, there is rumored to be a large chunk of ice from the Missoula flood buried under the slide. Early settlers in the region excavated a tunnel into it and used it for food storage at one time. It probably was known to the Indian tribes of the area though I haven't been able to find any documentation of that or the pioneer use, it's all been word of mouth. The entrance was knocked in several years ago when it had become a popular place for kids to go and drink beer and party in the summer (me included!)but you can still stand next to the caved in tunnel and feel the very cold air flowing out. Like I say, all word of mouth but I have talked to several old-timers who have heard of it. Is it truly possible the ice could have lasted this long? --killing sparrows 03:58, 12 April 2007 (UTC)

Ice in the Corfu Slide
Interesting idea that ice should have existed under the slide since 13,000-15,000 years ago. Let's consider if this is even credible...

Heat and cold tends to move into the earth in waves from the surface. After a distance of 10-15 feet, the seasonal variations tend to average out to the annual average. The annual average temperature in the region of the slide is about 48.5° F, so if you dig a tunnel 20 feet or more into the earth it would probably be about 48.5° F or 9°C. If its higher up the slope, it would be cooler, so say 8°C. When I was a kid we refrigerated butter and similar things down a dumbwaiter that lowered things into a cool, dry well sunk below the house - it worked very well (except for a musty smell) and used no electricity. So it is not unusual to find cool breezes draining from a tunnel. And if you have air flow the evaporation of moisture can cool it further (like a swamp cooler) - see Qanat for an insight on how that would work.

But let's look seriously at the possibility of ice.

Of course there’s another factor other than heat coming in. If a significant amount of heat is also coming up from below, common in areas where there are hotspots, this subsurface temperature can be higher. No reason to expect that is the case near the Saddle Mountains as the hot spot has moved on to the Yellowstone area. So we’ll neglect that heat source here.

Earth is a fairly good insulator – say the equivalent of concrete – so its thermal conductivity is about 0.8 Watts/meter-°C. Since ice must be 0°C or colder, if you have ice buried, for example, 100 meters into the hillside, the temperature difference is 8°C over that 100 meters. The heat flow rate = (thermal conductivity x area × temperature difference)/distance or for a one meter square area, 0.8 W/m-°C x 1 m² x 8°C/100 m, which gives you 0.16 Watts (0.16 Joules/sec). This is 5 Megajoules per year per meter². Since the latent heat of melting for ice is 334 Joules/gram, this will melt about 15,000 grams of ice per year. For an ice face 1 meter on a side (which is what this heat flow was computed for) and an ice density of 1 gm/cm³ this implies you’ll melt about 1.5 cm (or 0.5 inch) into the ice every year. In 15,000 years, you’d melt 8,900 inches or 750 feet into a huge block of ice. So a really big block of ice just might have survived for some time - maybe long enough to be found in the 20th century. But it would have had to have been almost absurdly large.

Of course many things would throw a rough-order-of-magnitude calculation like this off. For example, flowing water in the area would transfer heat much faster. And the average temperature over the past centuries was lower, so the melting could have been slower.

But all things being equal, it appears it may have been just barely possible if the ice block was large enough and the conditions were favorable. If you have any references – say old newspaper articles or the like testifying to witnesses seeing actual ice – this would be a great addition to the article.

And then we might be able to get some of the WSU geologists interested in studying the phenomena. Might be the makings of a Masters Degree in the study of vestigial ice-age ice from a glacier that is otherwise gone.

And it would certainly enhance the argument that the flooding of the rerouted Columbia was the proximate cause of the slides!

Thanks for the interesting thoughts Williamborg (Bill) 02:54, 13 April 2007 (UTC)

Ice Cave Update
Hi there, Well, sad to say the ice cave was not any remnant of the floods. It was dug by early settlers who would cut and haul ice from the Columbia river during the winter and then have 'cold storage' during the summer months. I talked to a gentleman who went with his father to do this very thing in the late 1930's. It was used until the 1950's and then with the availability of refrigeration, largely abandoned. The entrance started falling in sometime in the early 1960's and was then further purposely collapsed to prevent anyone getting in there and possibly being trapped. Too bad, it would have been a great find.-- killing sparrows  (chirp!) 00:59, 30 April 2007 (UTC)