Just heard that there is a preview feature that lets you control failover of your RA-GRS storage account.
From the docs.microsoft.com article:
Azure Storage supports account failover (preview) for geo-redundant storage accounts. With account failover, you can initiate the failover process for your storage account if the primary endpoint becomes unavailable. The failover updates the secondary endpoint to become the primary endpoint for your storage account. Once the failover is complete, clients can begin writing to the new primary endpoint.
Learn more about storage account failover here: https://docs.microsoft.com/en-us/azure/storage/common/storage-disaster-recovery-guidance.