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May 2026

29

What happened?

Between 04:24 UTC and 20:18 UTC on 29 May 2026, a service disruption affected multiple Azure services in the West US 2 region. Impacted customers experienced service connectivity failures, timeouts, and elevated error rates when attempting to access resources in the region. Additionally, customers may have experienced an inability to deploy new resources or scale existing workloads, intermittent availability where some requests succeeded while others failed depending on which infrastructure nodes had recovered, and both data plane and control plane impact across affected services. Impacted Azure services include, but are not limited to:

  • App Service (Web Apps), Application Insights, Azure Cache for Redis, Azure Container Registry, Azure Cosmos DB, Azure Data Explorer, Azure Data Factory, Azure Database for MySQL Flexible Server, Azure Database for PostgreSQL Flexible Server, Azure Databricks, Azure Functions, Azure IoT Hub, Azure Kubernetes Service, Azure Log Analytics, Azure Managed Grafana, Azure Monitor, Azure NetApp Files, Azure Policy, Azure Resource Graph, Azure Resource Manager, Azure Site Recovery, Azure SQL Database, Azure Storage, Azure Synapse Analytics, Backup (MAB), Microsoft Defender for Cloud Apps, Service Bus, Virtual Machine Scale Sets, and Virtual Machines


What do we know so far?

Our current understanding is that severe weather, including lightning strikes in the region, resulted in utility power loss to multiple datacenter buildings simultaneously.

Backup generators activated as designed; however, some datacenter areas experienced elevated temperatures and cooling-related issues. These infrastructure conditions led to interruptions for Azure resources hosted in the affected locations, and some customers may have experienced service unavailability, connectivity issues, or degraded platform operations.


How did we respond?

  • 04:24 UTC on 29 May 2026 – Customer impact began.
  • 04:24 UTC on 29 May 2026 – Service monitoring detected thermal and environmental alerts across affected regional facilities.
  • 05:00 UTC on 29 May 2026 – We determined that a power and thermal event had been caused by a severe thunderstorm in the region.
  • 05:36 UTC on 29 May 2026 – We began restoration of affected network components and dependent services.
  • 10:00 UTC on 29 May 2026 – We confirmed that datacenter power was showing initial signs of restoration.
  • 12:50 UTC on 29 May 2026 – We began to see initial recovery for affected downstream services.
  • 18:15 UTC on 29 May 2026 – Power was fully restored.
  • 18:37 UTC on 29 May 2026 – Recovery progress reached approximately 90%.
  • 19:34 UTC on 29 May 2026 – Recovery for the remaining affected services was confirmed.
  • 20:18 UTC on 29 May 2026 – After continued monitoring, we determined that remaining storage resources had recovered and final downstream services had been restored.


What happens next?

  • Our team will be completing an internal retrospective to understand the incident in more detail. We will publish a Preliminary Post Incident Review (PIR) within approximately 72 hours to share more details on what happened and how we responded. After our internal retrospective is completed, generally within 14 days, we will publish a Final Post Incident Review with any additional details and learnings.
  • To get notified when that happens, and/or to stay informed about future Azure service issues, make sure that you configure and maintain Azure Service Health alerts – these can trigger emails, SMS, push notifications, webhooks, and more:
  • For more information on Post Incident Reviews, refer to:
  • The impact times above represent the full incident duration and are not specific to any individual customer. Actual impact to service availability may vary between customers and resources – for guidance on implementing monitoring to understand granular impact:
  • Finally, for broader guidance on preparing for cloud incidents, refer to:
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