Users across the world have been unable to access critical Microsoft services, including Office 365 and Azure, for more than 24 hours after a "severe weather event" knocked one of its data centres offline.
Power surges to one of Microsoft's South Central US data centres, based in San Antonio, Texas, was caused by a bout of lightning strikes yesterday morning that forced it to power down from approximately 10am BST, according to the company.
Microsoft's Azure Active Directory service was also taken offline, impacting other IT products and caused some users predominately based in the US, UK, Northern Europe and Australia to lose access to Office 365.
The company issued a notice yesterday afternoon confirming a host of Office 365 services - including Exchange, PowerBI, SharePoint, and Microsoft Teams - had been taken out, as had a multitude of Azure-based services.
"A severe weather event, including lightning strikes, occurred near one of the South Central US datacenters," a message on Microsoft's Azure status dashboard read.
"This resulted in a power voltage increase that impacted cooling systems. Automated datacenter procedures to ensure data and hardware integrity went into effect and critical hardware entered a structured power down process."
"Engineers are prioritizing the restoration of Storage resources in order to recover all services with dependencies on these impacted resources.
"As storage mitigation continues to progress, a necessary extended mitigation phase is required."
While a handful of services have recovered, namely Office 365, after power was restored to the affected data centre, Azure customers are still experiencing difficulties.
Microsoft confirmed on its Azure status dashboard that engineers are actively working to recover impacted Azure Storage scale units and fully restore the remaining services.
DownDetecter shows a litany of complaints around Office 365 and Azure services flooded around the time Microsoft says the outage was first detected, while customers from across the world took to social media to complain about being unable to access the services they rely on, including from the Netherlands, the US, and Switzerland.
"Today's incident at Azure was another clear reminder for the need for organisations to build in their own redundancy rather than rely on a single vendor," said Mimecast's cyber resilience expert Pete Banham.
"All organisations, including Microsoft, need to consider what downstream effects there may be from losing a critical service due to technical failure or human error.
"Should employees around the world using Office 365 be reliant on a single Azure DC in the US? Services will always fail and IT leaders need to ensure they have not outsourced responsibility to a lone cloud service."
Banham's comments echo research published earlier this year that suggested the majority of UK businesses had not fully appreciated the risks of a cloud outage - and that they were putting their security at risk.
Reports from San Antonio, meanwhile, suggest the city is set for further weather disruption in the coming days.
Cloud Pro approached Microsoft for comment.
