Hello,
You might consider moving to another location.
The Heat may have been generated by your building the base and/or other around you.
I know there are others that have yet to see a screamer, near home. I am one.
I get roaming hordes but nothing like you describe.
I've purposely left forges on and put torches up to attract a horde. (When I am prepared for one, of course)
I get them but not the same as one called in by a hornet or screamer.
I am also far away from a town but close enough to get to one with a short 3 minute run.
**H0tR0d, this is NOT an invitation to spawn hordes on my base. ;-P **
I wish you luck and let me know if you need help with anything, in game. My general area is 3100N 300E.