Create a storage account and backup the public website.

To create a storage account and back it up, search and select storage accounts
Select +create
Click on the previously created resource group.
set the storage account to private
Review and Create

To maintain the storage in case of a regional outage, configure the appropriate level of redundancy.
From the storage account, in the Data Management section, select the redundancy blade.
Select Geo-redundant storage.
Refresh the page and save the changes.