A Threat List, as I understand it, is a list of events that you want to prepare for listed in the order they are likely to happen. This list tells you what to prepare for first.
This my understanding at this time. Your list is probably different. I would be happy to discuss any differences.
Here is my list (in order of likelihood):
1. Severe thunder storm resulting in short term power outage.
2. Severe snow storm resulting in work and school closings (and possible short term food shortage).
3. A hurricane that results in damage and short to medium term power outage
4. A tornado that results in damage/power outage.
5. A hurricane that results in severe damage (loss of home).
6. A snow storm that leaves me stranded in my car.
7. A tornado the results in severe damage (loss of home).
8. Economic collapse.
9. Nuclear war.
10. Terrorist attack resulting in a regional or nationwide grid down event.
11. A nationwide or worldwide grid down event caused by a solar flare or coronal mass ejection.
12. Pandemic resulting in 90% or more loss of life.
13. Asteroid/comet impact or other astronomical disaster (non-extinction level).
14. Asteroid/comet impact or other astronomical disaster (extinction level event).
I have prepared this list based on what has occurred in the past and the likelihood of certain major disasters that have not occurred.
Here is what has occurred locally (Trenton, New Jersey) in the past 20-25 years:
Numerous severe thunder storms some of which have caused power outages last from seconds to hours.
Snow storms that have resulted in work and school closings.
Some moderate hurricanes or tropical storms that have also resulted in power outages.
One tornado that did damage in the area.
One major hurricane/tropical storm (Sandy) that blew down trees and knocked the power out for 27 hours
Here is what has occurred regionally (New Jersey, Eastern Pennsylvania, Southern New York, and New York City) in the past 20-25 years:
Severe thunder storms (as above)
Snow storms (as above)
Moderate hurricanes (as above)
Flooding (both flash floods and river flooding)
A regional grid down event (power outage)
Other tornadoes that did damage across the area.
One major hurricane/tropical storm (Sandy) that caused severe damage across the region.
Two terrorist attacks (the World Trade Center bombing in the nineties and 9/11)
The possibility of economic collapse, nuclear war, or a nationwide or worldwide grid down event (power outage) caused by a solar flare or mass coronal ejection are discussed elsewhere. I think that any of them could happen tomorrow or never so they are less likely than the events listed above. Also, for completeness I will include an asteroid/comet impact (non- and extinction level events) which are even less likely.