We’ve had four days of nearly constant, heavy rain here in Fairbanks, and the levels of the Interior rivers and streams have come very close to the levels they reached in the Flood of ‘67. So we’re currently experiencing a 30-year flood event. The Tanana, Salcha, Chena and Nenana Rivers have all reached flood stages and many residents in low lying areas near these rivers have been evacuated. The photo on the right, taken by the National Weather Service, shows some of the flooding in the Rosie Creek area. Most of the larger rivers in town are six or seven feet above their normal summer levels.
The following plot shows the hourly and cumulative precipitation from the Small Arms Range (SRGA2) weather station over the past four days. Just under three inches of rain in four days doesn’t sound like a lot when you're from other parts of the country, but Fairbanks gets an average of less than two inches a month in July and August, and our total annual precipitation (including snow) is only 10.87 inches of water. Much of the lower elevation and north-facing areas in the Tanana Valley are permanently frozen and this permafrost is quickly saturated with water. That’s why the region is so lush and green in the summer, despite almost desert-like summer rainfall totals. But once the ground is saturated, there’s nowhere for the water to go except into the streams and rivers. Usually flooding happens during breakup when all the melting snow runs off the frozen ground into the streams and ice jams in the rivers block the flow. Summer floods are more unusual.
Since Labor Day, 2007, we’ve been living around 30 feet away from a small stream, Goldstream Creek, which has risen between four and five feet since last week. If you look at my previous post, the log I’m resting my hand on in the photo is now completely submerged, which means if I were swimming out there today, the water would be over my head. The outside bank has slumped into the Creek in two places, but so far we haven’t lost any trees. The photo to the right shows the current water level, but even with the dramatic rise, it’s quite a bit below what it looked like during breakup this spring.
It’s really exciting living next to something that’s changing all the time like the Creek (plus, Kingfishers!). And now that we seem to have survived a 30-year flood event, I feel a little bit more secure that we’re not going to get inundated in the next high water event.
I’m looking forward to the Tanana Valley Fair, followed by a warmer, and drier August and September.