Alaska winter highway weather

Driving in winter in Alaska can be interesting, to put it mildly. Driving around town is included in this statement but is certainly not like hitting the open highway, crossing vast, unpopulated areas and ascending and descending mountain passes while dealing with any combination of snow, ice, fog, white-out*, wind, extreme cold, long darkness or blinding sunlight. I would not want to miss this kind of adventure, though I approach it with due respect and sometimes apprehension. (*a white-out is a low contrast condition that makes it very difficult to judge distances, to see where the sky ends and ground begins, and to see ups and downs that might be ahead of you. Obviously not good for driving. In the photo below, the visibility is limited, but you can see the road for a ways and the poles on either side, put there for just this reason.)

Haines Highway with drifting snow, low visibility

Haines Highway, near the summit, with drifting snow, low visibility. Difficult, but drivable. The poles on either side of the road really help.

Since the winter weather has the potential to put a complete halt to highway travel, having an accurate forecast well in advance of a trip could save much time, money, missed opportunities, or worse. I consider this one of the most important uses of weather forecasting. Is the state of the art up to the task?

The state of the art

The raw truth is that there is precious little information available to meteorologists and the travelling public about the current weather (what’s going on right now) along Alaska’s highways. When you don’t have a good idea of the current conditions, its that much harder to make a forecast. The main problem is the enormous distances between traditional weather reporting stations. What about web cams? Yes, they do help fill some of the gaps, but they are restricted to areas with electrical power and telecommunications, so we are still left with vast stretches of mystery highway. Weather radar does not reach most of the areas of interest due to distance, and blocking of the radar beam by mountains (remember, the mountainous areas are the most critical for driving and also for affecting the weather). Satellite data is of limited help since it is not so good for inferring things like how much snow is piling up and whether there is reduced visibility due to falling or blowing snow. Much of the diagnostic work is done just as the prognostic work: by looking at the various charts and inferring the conditions on the ground, using local knowledge as a guide. All these challenges mean that weather info for the more remote sections of highways is not good enough to make a go/no go decision on a trip more than a few hours in advance. The good news is that if your are properly equipped with a good vehicle/tires, winter driving skills and provisioned for any contingency, you can most always make it through despite the weather, though the time needed may vary.

The targeted highway forecast

A few years back the NWS put out “motoring” forecasts for all the main year-round highways in the state. With two exceptions these have been absorbed into the “zone” forecasts. The thought was that the zone forecasts now cover the entire state, so the highways are covered in the various zones they fall in. So there is no need for a separate forecast. Well, I believe the change resulted in a decrease in service to the highway traveler. The reason is related to the reasons why it is so hard to forecast or even determine the weather along the highways. The lack of data encourages a forecast more tuned into the population centers and weather reports in the zone. The mountainous areas in a zone often have different weather and usually few, if any, weather stations. But the highways go through the mountains, nonetheless (yes, through passes, the low spots, so things aren’t as bad as they could be). The zone forecast can only stretch so far, and the highways (passes in particular) don’t get the treatment they used to. There are a few passes explicitly mentioned as locations included in the zone forecast, and that may help some, but there are only a few. Another issue is convenience: The route from Anchorage to Fairbanks passes through six zones. Other routes aren’t going to make you look up and piece together quite that many forecasts, but at least two or three.

The exceptional highways

There are two routes which avoided the axe: The Klondike Highway from Skagway to Carcross and the Haines Highway from Haines to Haines Junction. Maybe the need was seen for these two since they are two of the most weather-affected drives around, or maybe it had something to do with the international nature of the routes: both cross the coastal mountains while traveling between US and Canada. Perhaps the Canadian forecasters, who write the sections on their soil, wanted to keep it going. Either way, it is good that it is still done. In keeping with the difficulty of the task, the forecast is only valid for the current and next day (the evening version only for that night and next day, i.e.., 24 hours), and it doesn’t try to cover whether the road will be slick, icy, wet, dry etc. The forecast is released from October through April, which covers most of the possible poor driving conditions. Most, but not all. In June 2008 a large section of the Haines Highway was blasted with as much as a foot of snow!

These two remaining highway forecasts can be found at http://pajk.arh.noaa.gov/TextFcsts/textProds.php#prods=public.

Zone forecasts can be found at http://pafc.arh.noaa.gov/pubfcst.php.

Reading between the lines

As sketchy as they may be, checking the current conditions before heading out is crucial. Here’s a portion of the road reports for the two Southeast Alaska access routes mentioned above. This product comes out only once a day, in the morning. Notice that info from Frasier is missing. The report from the summit is valuable…those conditions are marginal but drivable. Another important bit here is the temperatures at customs (38F or +3C) and the summit (30F or –1C). The drop from above freezing to below freezing is most likely going to be the slickest part of the drive, and in this case it comes in the steepest section of the highway. Better have really good tires.

900 AM Saturday October 29, 2011

South Klondike Highway Weather Observations Between 7-9 AM Saturday

Mile Location SkyWx Temp Vsby Wind 24Hr Pcpn 24Hr Snow 24Hr Max 24Hr Min
0.0 Skagway Airport Light Rain 45 10+ SW14G21 0.02 M 47 42
6.8 US Customs Rain and Fog 38 7 S10 M 0.0 M M
15 Summit/Border Snow and Fog 30 3/4 S15 M 3.0 M M
22.5 Fraser M M M M M M M M
66 Carcross Cloudy 31 10+ NNE4 T 1.2 31 26

For the Haines Highway it might at first appear there is more complete reporting, but look at the mileage figures. The first 40 miles from Haines are along the river flats…very little elevation gain. After passing the border the road climbs aggressively and crosses several high points, followed by many ups and downs. [more details including a satellite photo and nifty elevation profile can be found at the website of the bike race that takes place on this route each June, the Kluane Chilkat International Bike Relay.] By the time you get to Blanchard, the next point with any weather information, most of the weather issues are behind you (assuming you are northbound). At least on the Klondike Highway there is some information about the actual pass, here, nothing. That the visibility is zero at the border and only 4 miles at Blanchard could indicate a slow drive.

Haines Highway Weather Observations Between 7-9 AM Saturday

Mile Location SkyWx Temp Vsby Wind 24Hr Pcpn 24Hr Snow 24Hr Max 24Hr Min
0.0 Haines Light Rain 40 5 CALM 0.09 0 43 37
3.5 Haines Airport Light Rain 44 10+ ENE13G22 0.02 M 45 39
23.8 Chilkat Rvr Bridge M 35 M CALM 0.03 M 42 32
36.6 Klehini M 32 M CALM 0.15 M 40 31
40.4 US Customs/Border Cloudy 32 0 M 0.00 0.0 41 30
88 Blanchard Cloudy 28 4 CALM T 0.8 34 21
151 Haines Junction M M M M M M M M

The reports from 23.8 and 36.6 are from DOT automated wx stations with web cams. You can get them through the DOT website at http://www.dot.state.ak.us/iways/roadweather/forms/AreaSelectForm.html, or the state 511 website (so names because you can dial 511 on your phone to access the information) at http://511.alaska.gov/. The latter I find slow and cumbersome but at times contains valuable road condition reports that the DOT does not, since the latter does not try to give road conditions, just weather. More web cams can be found at http://akweathercams.faa.gov/. Although indented for flying weather these cams can help with highway weather as well.

More info

Don’t forget to check the basic weather stations. They can be found many places on the web. Two good ones for this are http://pafc.arh.noaa.gov/obs.php and http://climate.gi.alaska.edu/Wx/current.html. The latter is map based,which should lend itself to highway planning (but the highways are not shone). Be careful with this one…for some reason the times of the observations are in east coast time, and, I’ve found several stations that are not mapped in the right place. It would be great to have a really good map-based web page that showed all possible observations, cams and reported road conditions (and forecasts for that matter). Another thing I’d like to see is a way for drivers to report conditions they encounter and have those reports available to other drivers. We get reports from airplane pilots and ships and boats, why not cars and trucks? What do you think? I’d love to hear your opinions, comments and questions via the comments link below.

Winter forecast

Yes, I’m working on a post covering what might happen weatherwise during the coming winter. It might not be out by Halloween (it could be scary enough), but soon after.

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