Opsgenie and PagerDuty let you add them as contacts from within the app and it manages the rotating numbers for you so you can keep using a specific ringtone for them. This is also how they can override DND so you can go back to muting your phone at night and know that pages will still come in.
FYI: Home Depot sells ratchet straps and rags for less than $10. First time I made this mistake with my car I just padded the roof with rags and ratchet strapped the shit to the roof.
The next time I went I had crossbars and used the same ratchet straps.
I’ve hauled more shit in my $16k sedan on $200 crossbars than 90% of $90k+ superduty pickup owners