Microsoft suffered “power interruption” at West US cloud region in February

Details problem in incident report, with full outage avoided

Microsoft experienced a “power interruption” at one of its US cloud regions in February 2026.

According to a Post Incident Report shared last week, the power issues hit the West US region, impacting availability between 07:58am UTC on February 7 and 04:24 UTC on February 8.

According to the report, the power issue meant that some customers experienced “intermittent service unavailability, timeouts and/or higher than normal latency for services.”

This was caused by a “power interruption affecting one of the data centers within the region, after which [the] impact manifested as infrastructure availability loss and service disruptions across multiple dependent workloads in the region.”

Microsoft said that as stabilization progressed, recovery “proceeded in phases,” though some storage and compute infrastructure were not restored immediately. This, Microsoft said, “slowed recovery for dependent components, and contributed to ongoing symptoms such as delayed telemetry and resource recovery.”

The power issues were related to an electrical failure in an on-site transformer, which Microsoft said resulted in the loss of utility power to the data center despite utilities still functioning.

“Although generators started as designed, a cascading failure within a control system prevented the automated transfer of load from utility power to generator power. As a result, Uninterruptible Power Supply (UPS) batteries carried the load for several minutes – until they were fully depleted, leading to customer impact from this power loss as early as 07:58 UTC.”

Microsoft turned to on-site generators, bringing power back to around 90 percent of IT racks by 09:31 UTC, but subsets of equipment needed “further electrical control system troubleshooting before power could be restored.”

By 11:29 UTC, the data center was fully operating on the generators.

The power loss affected six storage-scale units within the data center, four of which were recovered quickly, but the other two experienced “prolonged recovery.”

“Due to the dependencies that many compute and platform services have on these storage scale units, there was a delay in overall service restoration.”

Microsoft was able to return to utility power on February 9 at 03:42 UTC.

Microsoft has three West US regions; the West US location is in California, while West US 2 and 3 are located in Washington and Phoenix, respectively. Only West US 2 and 3 have “availability zone support,” meaning there are multiple data centers within the region that can be turned to during times of failure.

The outage came just a few weeks after Oracle experienced issues at a data center after a winter storm caused a power outage. The data center in question was one of TikTok’s primary sites, though the exact location was not stated. Storms swept through the US in late January, impacting around 20 states according to NOAA, as the harsh weather moved eastward.