Cerro Grande Fire

Cerro Grande Prescribed Fire Investigation Report - May 4-8, 2000

Introduction

Fire personnel at Bandelier National Monument, National Park Service (NPS) in New Mexico prepared a prescribed fire plan for the Upper Frijoles Units 1 and 5, now known as the Cerro Grande Prescribed Fire. The units encompassed approximately 1,000 acres in the headwaters of Frijoles creek above State Route 4 to the park boundary at Cerro Grande summit. This prescribed fire was part of the 10-year prescribed fire schedule approved in the fire management plan for Bandelier. The prescribed fire was scheduled for a three-phased treatment. Phase 1 consisted of burning grasslands in the upper part of the units. Phase 2 was the forested area on both the east and west side of the drainage, and Phase 3 was the central wetter area. (See Figures 1, 2, and 3)

In the late evening on May 4, 2000, the prescribed fire project was initiated. The intent was to back the fire down from the ridge and then extinguish the lower edge of the fire in the grass fuels. This would create a buffer of burned area between the park boundary and the areas to be included in Phases 1, 2, and 3. The ignition proceeded slowly and only when the ignition pattern changed did the spread and intensity increase. The fire burned through the control line (slopover) on the upper east side of the prescribed fire area during the late morning hours of May 5. Even with this slopover outside the prescribed fire area, the burn boss believed the prescribed fire remained within prescription. Fire personnel worked to suppress the slopover while continuing to hold the line around the remainder of the area they had ignited. They ordered additional resources in accordance with the contingency plan written in the prescribed fire plan. The contingency resources consisting of an additional crew and a helicopter were on the fire by late morning, but by early afternoon on May 5, the slopover continued to be a problem and the crew requested retardant to control it. This retardant request made the burn boss reconsider if the prescribed fire was still within prescription. It was not. The decision was made to declare the prescribed fire a wildland fire and initiate appropriate responses. A Type 3 incident command was established with existing personnel. On May 6, fireline was constructed down the ridges using pre-existing control lines, and strengthened using limited ignitions. The crews tied the line in with State Route 4 early on the morning of May 7. Crews then ignited along the road beginning on the east side working west to connect the east and west sides and closed off the fire area.

At noon on May 7, stronger winds influenced the fire area and the fire behavior became increasingly erratic and spotting occurred from a southern point into Frijoles Canyon. This forced a decision for park management to order a Type 1 Incident Management Team to assume command of the wildland fire. By mid afternoon, additional spotfires were reported east of the fire on National Forest System lands, and were rapidly increasing in intensity. These spotfires represented a potential threat to the Los Alamos National Laboratory.

A Type1 Incident Management Team assumed command of the fire in the early morning of May 8. On May 10, the Cerro Grande was a running crown fire that burned into the town of Los Alamos and threatened neighboring White Rock. There were 235 homes destroyed and approximately 18,000 residents were evacuated.

• Figure 1. Bandelier National Monument and Vicinity (PDF)
• Figure 2. Bandelier National Monument Prescribed Fire Units 1&5 Boundaries (PDF)
• Figure 3. Bandelier National Monument Prescribed Fire Units 1&5 Project Map (PDF)

National Park Service Cerro Grande Fire Website