Heavy rains earlier this month triggered a series of landslides on Thursday, Sept. 18, that covered a 100-acre section of the Starrigavan Valley, a popular recreation area about 10 miles north of downtown Sitka.
While the three landslides caused no structural damage, they caused hundreds of thousands of dollars worth of damage to USDA Forest Service watershed restoration projects, and caused extensive water damage to an ATV trail and several hiking trails in the area, including the Herring Cove Trail, according to a Sept. 24 news story on KCAW-Raven Radio.
According to a USDA Forest Service, Sitka Ranger District, preliminary analysis of the slides from Monday, Sept. 22, “The slide and its run out zone encompass approximately 75-100 acres, with an unknown number of additional acres also affected. The slide also directly impacted approximately 850m of Class I fish habitat along the mainstem North Fork Starrigavan Creek along with unknown lengths along several Class I tributaries. Other known damage at this time includes: three coho rearing ponds obliterated with one more severely impaired, two fish pipes blown out, one log stringer bridge destroyed, two trail sections blocked, and approximately 300 meters of OHV (ATV) trail/road eroded or buried.”
Both the Herring Cove Trail and the Starrigavan Valley were probably affected by what USDA Forest Service Watershed Program Coordinator Marty Becker calls a “micro-burst,” KCAW reported. Meteorological data for Sitka doesn’t indicate rainfall amounts too extraordinary for this time of year, but the rain came hard and fast. What was officially recorded as 3 1/2 inches of rain at the Sitka airport on the day the Herring Cove Trail was damaged, Becker says filled rain gauges in some parts of town to nearly seven inches.
Sitka naturalist Matt Goff, who writes the Sitka Nature blog, took his kids to check out the damage on the weekend after the slide, and he posted several photos on his blog showing trails that now look like small rivers, huge log piles full of uprooted trees, and other damage. He said there was an aerial map posted as you entered the area, showing which trails were impassable. He also wondered how the damage might have been different had there not been clearcutting in the area 40 years ago.
USDA Forest Service Recreation Manager Mike Mullin told KCAW, “The couple of events we’ve had this summer have been a little out of the ordinary for sure, but yeah, we’re not even in the rainy season, and we lose our seasonal crew in a couple of weeks. And obviously Forest Service budgets for maintaining trails are on the decline. So we’ve got a lot of things working against us.”
While there have been hikers and others out in the slide area recently, the USDA Forest Service said the soil is loose in many areas and still prone to slides, and it was delaying its final assessment of the damage until after the area settled. Even Goff said he had second thoughts about the safety of hiking in the area, especially after he had a chance to see some of his photos.