One lightning strike was enough to take out a significant portion of Amazon’s EC2 and an unknown part of Microsoft’s cloud services in Europe.

Amazon said that the lightning hit a transformer near Dublin, Ireland just before 8 p.m. local time on Sunday and caused enough disruption to send its servers offline. Within two hours, the company provided first details about the service disruption and began restoring server instances again after three hours. The company told its users that it would need 24 to 48 hours to get all services back online.

While having servers offline is painful, some EC2 customers were told that the data on their servers may not be in perfect condition. Amazon said that some EC2 instances or EBS servers lost power before writes to their volumes were consistent, and left Amazon only with the option to give its customers a recovery snapshot. Before the instances are restored, the customers were asked to validate the status of their data.

Microsoft apparently was affected by the lightning incident as well and told its users via Twitter than certain cloud services of its Business Productivity Online Standard Suite were offline. Microsoft kept a lid on the information available to the public and provided details of the service disruption only to its customers.