By Steve Ulvi,
Few “natural” events wreak havoc like large fires in western landscapes. Increasingly, the transformative rampage of turbo-charged wildfire rips through control measures and inadequate agency budgets. Large-scale climatic factors and American lifestyle choices are locked in ever-more destructive and costly feedback loops.
A few decades back, I trained as a Fire Behavior Analyst in my resource management job in a huge new National Preserve in Interior Alaska. Thus began a plunge into the profound, rapidly evolving scientific and technological advancements within wildfire behavior prediction, amassing remote weather data and prescribed burn planning. Billowing thunderheads over a grand mosaic of historic burns fueled my fascination with the ongoing interplay of wildfire and taiga ecology in the vast Yukon River basin.
On San Juan Island – care in outdoor activities, banning fireworks, Fire Wise efforts and well-trained local crews – ought to be pretty reassuring. Yet many residents fret about island fires imagining a tempest of flames and burning homes as portrayed in dramatic Western news stories. Recent intensified clearing by contractors beneath OPALCO transmission lines is obviously helpful in reducing winter blowdown interruptions and expediting maintenance access. But website PR statements justifying extensive clearing with claims that “wildfire is a critical problem…” are hyperbolic and unnecessarily alarmist.
The simple truth is that our maritime conditions are rarely conducive to sustained blazes. Take a look around. Never say never; but there are several key factors that make our short summer profoundly different from east of the Cascades, California, or southern Alberta that greatly diminish fire ignition and control problems.
For example, our surrounding cold-water dissipates the energy of mainland thunderheads that wander this way. Hence, lightning strikes are rare and “wet”. These waters also increase relative humidity. The summer ambient air temperature drops at night, elevating relative humidity thus dampening flammable fine fuels. Woody debris on the shaded forest floor slowly dries during summer but is drenched every winter. Foliar moisture content in summer needles and leaves remains high. Most importantly, we enjoy light and variable summer breezes rather than strong thunderhead downdrafts or howling topographic winds that generate extreme fire behavior in other regions.
Our few human-caused blazes every summer typically ignite and spread in roadside dry grass, can be effectively attacked with water and seldom climb into the overstory. Lots of control lines exist; hardwood stands, roads, wetlands, ponds and landscaping breaks. Woody debris beneath cloaking fir stands can burn intensely but spreads slowly.
The “rest of the story” is that our long-standing conditions are being altered by accelerated regional climate change trending toward higher summer temperatures and longer drought conditions. The increasingly erratic jet stream can lock in a dome of high pressure to the east (as happened two summers ago) creating periods of very high day and night-time temperatures and hot air blown in by offshore winds from the dry east side of the Cascades. That temporary situation, likely to be increasingly common as arctic sea ice disappears, will be a real cause for worry.