The first official review of the Los Angeles wildfires found that the county’s emergency systems were not only overmatched by hurricane-force winds, but also hampered by outdated equipment and a lack of aerial surveillance that kept firefighters from clearly seeing the path of the flames.

The 133-page report, released on Thursday, found no “single point of failure” in the county’s efforts to warn and evacuate residents.

But with winds gusting up to nearly 100 miles per hour, firefighting fixed-wing planes, helicopters and other aircraft were grounded, depriving fire officials of any aerial view for several critical hours. A nearly four-decade-old dispatch system hampered communications. Emergency workers were spread thin by staff shortages that included more than 900 sheriff’s department vacancies. Digital warnings had to go through a cumbersome approval process, and failed to get through to many people’s cellphones, possibly impeded by power shut-offs and spotty cellular coverage in mountain areas.

The effectiveness of the county systems that alert residents and order evacuations were impacted by “a series of weaknesses, including outdated policies, inconsistent practices, and communications vulnerabilities,” the report stated.

The review was conducted for Los Angeles County by the McChrystal Group, a consulting firm led by Stanley McChrystal, a retired four-star general. It was one of at least a half-dozen local, state and federal reviews to be commissioned in the aftermath of the disaster, which raged for nearly a month in January across some 37,000 acres in Los Angeles and surrounding suburbs, killing at least 31 people and destroying more than 16,000 structures, most of them homes.

Six separate wildfires ignited across Los Angeles County during the first two days of the disaster, the review found, with fire crews at one point stretched across five of them simultaneously.

Twelve people died in the Palisades fire, which ignited on the morning of Jan. 7 in Pacific Palisades, an affluent coastal community within the Los Angeles city limits. Nineteen more were killed in the Eaton fire, which erupted hours later around dusk in the foothills of the San Gabriel Mountains, roaring on powerful winds down into Altadena, a suburb of Craftsman bungalows and ranch homes about 35 miles to the east.

The review did not explore the causes of the fires, which are still under investigation, nor did it seek to “investigate wrongdoing or assign blame,” according to its authors. Rather, it focused on one of the more broadly debated aspects of the fire response — the effectiveness of emergency warnings and evacuations.

Although California is renowned for its cutting-edge firefighting, survivors of the Los Angeles fires complained almost from the start about the timing and accuracy of electronic alerts and evacuation warnings.

In at least one of the areas that was leveled, West Altadena, a community that falls under the county’s jurisdiction, anguished residents reported that they did not receive an evacuation alert until the Eaton fire was almost upon them. Some homes were in flames before their owners received a warning. All but one of the people who were killed in that fire died in the West Altadena neighborhood.

Meteorological forecasts had warned since New Year’s Eve that a dangerous windstorm was on the horizon, the report found. In areas long accustomed to wildfire, such as Malibu and Topanga Canyon, many people understood the danger even without an official warning, and evacuated on their own initiative.

In the San Gabriel Mountains, the wind speed was so lethal that firefighters were able to operate fixed-wing aircraft for only a half-hour before they were grounded, the report said. The situation not only prevented them from dropping fire retardant, but also stymied their ability to view the fire’s path from the air.

An hour or so into the Eaton fire, with the wind carrying the flames toward the foothill suburb of Altadena, officials issued an evacuation order just for the east side of town, where the fire appeared headed. Upwind, on the community’s west side, residents were left to determine for themselves whether to flee their homes.

But as the wind carried embers for miles and fed flames that shot 200 feet horizontally against the night sky, it became clear to crews on the ground, the report stated, “that they were facing a fire that would eventually spread everywhere all at once, rather than a single line of fire moving in one direction.”

Los Angeles County firefighters in the field told investigators that shortly before midnight, they suggested to the disaster’s unified command that perhaps evacuation orders should go out across all of the foothill areas of Altadena, not just to the east side. But the commanders in charge did not recall that suggestion, the report said.

At the time, the report added, emergency officials were dealing with a multitude of issues, including an urgent fear that a catastrophic inferno would reach the nearby NASA Jet Propulsion Laboratory, where facilities in the path of the fire were filled with deep space robotics equipment and toxic heavy metals. The laboratory ultimately survived.

Shortly after 1 a.m., the report said, county sheriff’s and fire officials, who jointly determine evacuations, stopped instructing the county’s Office of Emergency Management to issue evacuation warnings and orders in the Eaton fire, believing that all of the residents at risk had already been warned or instructed to get out. In fact, at some point that night, the fire had shifted, muscling back toward West Altadena on the Santa Ana winds.

It was not until after 2 a.m. that commanders, alerted by reports from the field and radio chatter, realized that the fire’s direction had changed and that thousands of people in West Altadena were now in its path, according to the investigation. At 3:25 a.m., residents in the neighborhood received their first alerts. About an hour and a half later, at 5 a.m., the Eaton fire crossed Lake Avenue, the dividing line between the east and west sides of Altadena.

“While frontline responders acted decisively, and in many cases heroically in the face of extraordinary conditions, the events underscored the need for clearer policies, stronger training integrated tools and improved public communication,” the report found.

Since the fires, county officials said, a range of updates have been made in emergency procedures, including the incorporation of more satellite data into its incident command management system, a modernized communications dispatch system and new policies that now automatically augment evacuation orders with additional evacuation warnings for people living in adjacent neighborhoods.

Nonetheless, Los Angeles County supervisors, who commissioned the report, vowed to further improve emergency warning procedures.

“This isn’t about pointing fingers,” said Kathryn Barger, the chairwoman of the Board of Supervisors, whose district includes Altadena. “It’s about learning lessons, improving safety and restoring public trust.”