Post Storm Assessment In the Colby Fire Impact Area
November 21, 2014
This was a surprise storm for the Colby Fire Impact Area. Initial predictions from the National Weather Service indicated 30% chance of storms and rain fall below threshold levels for debris flows. Yet all entities ranging from the Weather Service to Fire agencies to City Public Safety have consistently warned that weather modeling cannot always be correct and that’s exactly what occurred on Friday, November 21, 2014.
A significant thunderstorm cell formed in a very small geographic area over the Foothill areas between Azusa and Claremont. In fact, areas of Glendora south of the freeway received only the predicted light rain that the Weather Service had indicated. This thunderstorm was intense and quick. It began around 1:50 am and lasted until about 2:30 am on Friday. In that time period we received about .75 inches of rain, and during a single 10 minute period the rain fell at a rate equal to 2 inches per hour.
The result of the thunderstorm triggered mud flows equal to a Phase 2 levels – one level below the most extreme flows possible. The flows were most significant along Easley Canyon; Glendora Avenue, Palm Drive; Mullaghboy Road; Vista Bonita; Grand Avenue; Rainbow Drive; Hicrest Drive and Country Club Drive. Other streets had flows but these received from 7 inches to 7 feet of debris.
Our mitigation measures worked extremely well during this event. We had no injuries and only one residential structure suffered some minor damage. Several properties had significant debris deposits on their property.
To date we have removed about 50 dump truck loads of debris and will continue to remove. The event will require significant follow up with street sweeping to help remove the finer mud and dust control. Los Angeles County Flood Control reports that they will need to remove approximately 45,000 cubic yards of debris from their five debris basins in order to be prepared for the next storm event. That removal will begin in early December and a schedule will be posted on this website. The special street sweeping schedule is already posted on this site along with a map depicting the schedule.
Resources involved in this storm event were numerous. Approximately 45 maintenance staff members from the City’s Public Works and Community Services Departments were assigned tasks for a 12-hour time period; Glendora Police Department dispersed 12 officers and support personnel. Los Angeles County Fire Department responded with approximately 80 personnel from the initial call out to sunset. Many of those responding for Los Angeles County Fire were from Fire Camps #19 and #2 which assisted in hand digging in areas where equipment could not be used.
We again remind residents living in the Colby Fire Impact Area to always be alert and aware anytime rain is forecasted or the skies look like rain could occur. While our critical partners with the Weather Service work extremely hard to give us the best information and modeling possible, this event should remind us that unplanned storms can and will occur over the next four to five years. So being informed, prepared to act quickly and following instructions from the City of Glendora are important part of our mission to protect life and property.