Saturday, October 14, 2017

Santa Rosa Fire Notes - My Old Town

I have a more than passing interest in the wildfire that burned into Santa Rosa. I lived there and taught school there for three years. The fire that burned into the north portion of the city torched hundreds of homes within a very urban setting within 3,000 feet of where I lived. A very humbling thing to contemplate that homes in an urban neighborhood were at risk from a wildland wildfire. Wind and heat matter.

This map https://api.mapbox.com/styles/v1/robinkraft/ provides an interactive viewing of the burned area with infrared imagery.

Screen shot of the burnt neighborhood
Red areas are live vegetation

I wanted to get a sense of some of the areas that burned associated with this fire. The fire start was from north of the map program (there are other burned areas covered as well shown on the map).

The fire reached the northeast part of the city in Rincon Valley. The fire had burned through very steep rugged hills that are a mix of grass, thick brush, oaks and drought tolerant pines. A very fire prone ecology. Stopping a fire in hot windy weather in that terrain would have been impossible. The Rincon Valley is a mix of small farms, semi rural/suburban area on the north and urban on the south.

Infrared image of burn area along the north edge of Santa Rosa in the Rincon Valley.
Arrow shows the approximate direction the fire burned.

Approximately the same area via Google Earth (July 2016)

Much of the Rincon Valley near the city edge is grass land. The area gets over 30 inches of rain a year so the grass grows very thick and tall through the winter and early Spring. Typically by June things are already fairly dry. The  The grass readily burns and burns fast. Based on infrared image the fire did not kill the trees. A grass fire through a stand of trees often does not damage the trees. That said, this fire moved very fast and burned into the edge of the city shown above destroying dozens of homes.

Destroyed homes south of grass field 

I did a street view tour of  the ground in the Rincon Valley along a former running route that I used to run on Wallace Drive. The street view images are from June 2016.

View looking east towards the rugged hills on the east side of Rincon Valley  


This field was plowed - a very good way to reduce wild fire in this setting

However. across the street, to the west was an unplowed and ungrazed field.
Note the trees become thicker and dense up the slope in the distance.

Infrared of street views shown above

It appears that the perimeter of the field shown above is routinely plowed in late Spring. Some homes were destroyed in this area as the fire burned through, but may of the trees survived and still have their leaves. 

To the west of Rincon Valley the landscape changes as does the vegetation and then again the densiy of homes.

A forest and brush covered ridge bounds the west side of Ricon Valley with much denser housing on the west side of the ridge

The fast moving grass and brush fire with high wind and heat pushing it must have burned up the ridge into that dry forest and brush and exploded into the suburban homes nestled into the forest and brush landscape.
Street view of the ridge area
Chaparral and pines and homes 

Nearly every home in this suburban neighborhood was burned. I tried looking at roof types and building materials via street view. Wood siding and asphalt roofs were allowed in this suburban neighborhood. That said, there were tile roof and stucco homes that burned. One odd home that did not burn in the middle of the conflagration had an asphalt roof and wood siding.

Why this house? Arrow points to a house that did not burn

The burning of the Coffey Park area on the northwest part of the city is the truly humbling aspect of this fire. The neighborhood was flanked by urban commercial and light industrial buildings as well as a 4-lane divided highway. The fire jumped the highway and hundreds of homes burned out of control well outside the much discussed wildland/urban interface.





A lesson every fire person knows - a fire with heat and wind will find any bit of fuel to burn.



No comments: