Try not catching Drive_not_found

I was surprised that the below checking of a non-existing drive does not transfer control to the Catch area. Why is that?

$DebugPreference = "Continue"                         

try {
    Write-Debug "Before Error"
    Get-ChildItem -Path "Q:\"    # Q is a non-existing drive.
    Write-Debug "After Error"
    Write-Debug ("Error in Try block: " + $Error[0])
}
catch {
    Write-Debug "Catch"
    Write-Debug ("Error in Catch block: " + $_.Exception.Message)
}

-Tom. Microsoft Access MVP