General Climate Discussion

[Baitman]

BTW, I always pictured Alaska as further North. I've been fishing further North than the arctic circle, up to like 67 degs. It was normally Ice free....

Angus 67 degrees doesn't even get us off the mainland. Canada goes much further North (So does Alaska). 

[Angus]

Out of complete curiousity, how far south does the permafrost reach?
(I mean Alaska, more like nearer to the coast, or Canadian coast, continental climate is another thing...)

[Baitman]

I really don't know how to post a picture but here is a link

http://http-server.carleton.ca/~msmith2/current_pf.htm

Map of permafrost in Canada

Just because it shows a southern limit doesn't mean that it doesn't come further south. I have run into permafrost drilling in Central BC.

[Angus]

Quite some map!
We have none. Living at 64 degs north.
Just the temporary wintermonths, but in the last few years we have been able to do fieldworks at unknown dates. Normally the ground would freeze in the autumn, and ploughing could be expected to commence in april-may with frozen pockets untill june/july. Now I was ploughing in February....

[Baitman]

Typically we can work the fields as late in the year as mid november. The freezing doesn't affect us if we have little moisture but if it rains a bunch in the fall we are done. Snow fall will hit the mountains and stay first part October but never in my Valley much before November.

In the Spring snow is gone mid march and we are planting early to mid april depending on the amount of rain delays we get.

You will notice the Alpine Permafrost on the map it runs south down the mountain ranges. I have personally seen this permafrost and at depth 100 - 200' down.

[AKIron]

I blame Obama. Just the threat of change is melting the polar ice cap. Do you want change or not?

[Angus]

So you get a proper snowfall before it freezes?
Our problem is a soaked ground that freezes. Then when it thaws you just have to wait, for it turns into complete mud for a while.
But in the last years this has been changing, so now we have winters where the frost doesn't settle in for the season. So we have a warmer ground at springtime, and winter possibilities with fieldwork, which is all good. The downside is droughts and new pests and insects.

[Baitman]

If it freezes before the snow comes and there is moisture in the ground to freeze, the snow will act as a blanket and the frost will actually leave the ground under the blanket of snow. This is how we lose much of our snow during the winter (it balances though little snow it will lower ground temp and the snow will stay).

I was talking to a buddy this morning just back from drilling in Greenland right next to the ice sheet. He claims that he never ran into any perma frost what so ever at depths to 1500'.

[Angus]

What part would that have been? Greenland has basically just rock and then ice, no 1500 feet of anything in between....

[Baitman]

I don't know the accurate location (privacy for the mining company) but they were drilling in the bedrock (overburden <10') and experianced NO permafrost even at depth. This is not common because in Canada we can find it, quite often we don't have to be close to any ice.

[Angus]

Well, you wouldn't find permafrost deep into rock, now would you?
Anyway, there are many companies over in Greenland on search for materials due to more land being exposed, one material being Gold.
Greenland is actually a very old chunk with various rock formations, but very much stone hard Granite I understand.
The rock is very hard, and hard enough for some of the toughest drillers to call it a challenge.

[Baitman]

Depending on the area we have had permafrost on the surface to 500+ feet down. In other areas the top layer is unfrozen and we run into permafrost at depth. Just depend on the area. Our land is colder than Iceland Geothermally heated land. I have held my hand in groundwater that is at freezing but with pressure and movement it keeps fluid.

[Angus]

Groundwater here cruises at 4 degs Celcius normally, sometimes down to 2.
BTW the Ice age layer where I live is some 12 feet down. But no permafrost there, since it's an old seabed, I guess the Ice-age didn't get there.
But in Greenland you have a glacier dating beyond the last Ice-age, if my memory serves me. But mostly resting on dry and solid rock, so no permafrost....

[Baitman]

Angus

Just because it is solid rock doesn't mean that it can't be permafrost. The rock will cool to below freezing and any water that will migrate into the cracks will freeze solid. Permafrost can be found in the unconsolidated (gravel, tills, clays) and consolidated (bedrock, solid rock)

Where I live in a very large glaciated valley we have areas that have multiple glaciations and they have all left their mark. Sometimes the later glaciation do not remove all what is left from previous glacial movements.

[Angus]

In Greenland the rock is very dense and hard. The water within (which is always some I guess) is at least not enough to crack it.
So, in truth the rock may be under zero. Wonder how thick though. A whole new field to look into.