Chilkat Valley News - Serving Haines and Klukwan, Alaska since 1966

Dear Precipitation Ponderers-

There are way too many factors that affect the snow-to-rain conversion calculation for me to give you a definitive answer. Ground-level air temperature and relative humidity are two factors, but they can vary significantly from those conditions at cloud level, and temperature gradations between the air down low and up in the clouds strongly influence the way that water droplets crystallize into snowflakes. Best I can do is to use a rule of thumb: for Fahrenheit temperatures between 20 degrees and 25 degrees, the rule says to multiply rainfall in inches by fifteen. Some stations reported ten inches of rain falling during the recent, tragic flood event. That would have been about 150 inches, or twelve and a half feet of snow!

Your follow-up question requires consideration of how the community deals with heavy snow. Haines is well-equipped for snow removal, and experienced in dealing with it, residents and municipal workers alike. When heavy snowfall is accompanied by high winds, the city and borough plow crews have a tougher time staying ahead of drifting snow, and school and road closures often occur in those conditions. Over twelve feet of snow, even without drifting, would be a tough task to cope with quickly. I’d assume that we’d have dealt with power outages, road closures and would be basically trapped in our homes until we dug out. Homes not designed well for snow load on roofs would be would be at risk of damage, even total collapse. The overall impact of so much snow falling so fast would have a lot to do with what the weather did next. If it stayed cold during the dig-out period, our infrastructure and residences would likely come through just fine. If there was a rapid warming and melt-off, flooding and slide events would be probable. A delayed disaster could occur even months later if huge snowpack at higher elevations melted off too quickly in the spring. All things being equal, heavy snow poses less risk of disaster than heavy rain, but the melt-off rate can certainly determine whether or not similar results might ensue.

As for the other question: while our temperate rainforest climate in Southeast Alaska means that fluctuation above and below the freezing point all winter is normal, and has been for all of our recorded weather history, the total amount of liquid precipitation in January has been truly “spectacular.” For this reason, I cannot agree with the oft-repeated assertion that what happened December 3rd was a “200-500 year event”. That sure feels reassuring, and tempting to believe, but even a cursory study of the weather worldwide for the past ten years shows clearly that extreme weather events are becoming increasingly frequent. There are essentially no bona fide scientists left in the climate change denier camp. The rain this past weekend (and all of January) suggests to me that Haines will see more disastrous weather much sooner than the year 2220.

Call 766-2688 or email chilkatnews@gmail.com with your science questions for Mr. Fontenot, science teacher at Haines High School