Question about North Coast Alaska Sea Ice?? (Barrow, Prudhoe Bay: travel, work)

[CometVoyager]

My cousin Bob returned from Barrow about 2 months ago and he told me the average temperature may have only gotten as high as 5 degrees Fahrenheit.

Was curious about the Sea Ice on the North Alaskan Coast. Does it lstill ast throughout the summer? My Uncle who used to go there in the early 30's said there was not ice there during the summer months but in the 1970's many reported year round sea ice with a significant thickness.

Would appreciate your feedback!

[Floyd_Davidson]

Originally Posted by CometVoyager

My cousin Bob returned from Barrow about 2 months ago and he told me the average temperature may have only gotten as high as 5 degrees Fahrenheit.

Two months ago would be in early April, and the average daily temperatures might be just about that. The average daily low temperature for the entire month of April is -8F. The record cold temperature for April is -38F.

I just looked up the data for April 5, 2008, and the high was 25F, (average high on that date is 0F) the low was 12F (avg for that date is -14F). So, at least on April 5th, it was rather warm.

Originally Posted by CometVoyager

Was curious about the Sea Ice on the North Alaskan Coast. Does it lstill ast throughout the summer? My Uncle who used to go there in the early 30's said there was not ice there during the summer months but in the 1970's many reported year round sea ice with a significant thickness.

There were one or two years in the late 1960's or early 1970's when sea ice blocked barges going to Prudhoe Bay until late September or early October, but they did make it through every year.

A description of how sea ice along the Arctic Ocean coast of Alaska works might help. There are two forms of ice that are interesting. One is "multiyear" ice, the other is ice that formed this year. The ice along the shore is all ice that forms this year.

Each year the ice pack recedes away from Alaska, and from Barrow the closest pack ice in mid-summer is north and somewhat east of Barrow. As winter comes on, ice forms on the ocean and the icepack expands again towards the coast. Historically the distance from Barrow to the nearest pack ice would have been less than 100 miles, but in recent years the pack ice has been more than 200 miles every year, and more than 250 miles in the last 2-3 years.

When the ice pack expands far enough that it comes into contact with the new ice that has formed on the ocean, it pushes that ice towards the shore, jams it all together, causing ice ridges to form, and making it extremely rough to travel over. Because the water is very shallow, ice is litterally piled up on the bottom of the ocean any place close to shore. That ice freezes to the bottom, quite solidly.

Comes spring time, there are, on the ocean side of those ice ridges, open leads as the pack ice moves with the wind. That is where the spring whale hunt occurs. And then later, when the pack is begins to seriously recede with warm temperatures (late May through July), the shore ice remains in place because it has been piled up on the bottom in places and cannot move until enough of it actually melts to allow it to float off, and that also only happens when a wind storm comes along and gives it a shove. (Keep in mind that there is virtually no tide here, only surges of a few inches that result from wind.)

So today, for example (in early June), there is ice from the shore extending out a mile or two. The pack is significantly more distant if the wind is in the right direction, or closer if not, but is not pushing on the shore ice any more. Between now and the middle of July the shore ice closest to shore will melt enough for boats to be launched, and seal hunting will begin. Eventually the ice will melt and the wind will blow it free, and it will all be floating around... which is great for seal hunting. But soon enough the wind will be in the right direction to blow it all away! And by late August it will almost certainly have gotten warm enough to melt virtually all of it.

Note that 30 years ago it did not get so warm as to melt it all, and there would be ice floating around just about anywhere, depending on the wind direction. In fact, only 8-12 years ago that was still true, but has generally not been true in the last 5-6 years.

[IceCold]

Wow, that is fascinating. Really.

I guess it just confirms the following NASA data:

(view movies #5 & #7)

NASA - 'Tipping Points' High-Resolution Multimedia for the 2007 AGU Press Event