Azure Blob Update Tier

In PowerShell:

$StgAcc = "<StorageAccount>"
$StgKey = "<StorageKey>"
$Container = "<Container>"
$ctx = New-AzureStorageContext -StorageAccountName $StgAcc -StorageAccountKey $StgKey

#Get all the blobs in container
$blob = Get-AzureStorageBlob -Container $Container -Context $ctx

#Set tier of all the blobs to Archive
$blob.icloudblob.setstandardblobtier("Archive")