Good question. Two points. First, disasters are typically measured by economic impact, not lives or environmental damage.
So, the Black Forest Fire(good wiki entry) is the “worst in state history” due to the number of homes destroyed, which is now close to 500.
Agreed. There were many other fires in Colorado that were geographically larger, destroyed more volumes of trees and habitat, killed more animals, and killed more people.
Natural disasters that kill a lot of people are categorized as “deadliest” (here’s a list). Damage to ecosystems are categorized as “environmental disasters” (this later category is, if memory serves, unofficial and possibly arbitrary since disasters are measured by relative [shorter term] economic impact).
Second point is there are known, but little discussed, problems in the field of journalism. Among them: Using proper definitions; filtering bias; incorporating appropriate perspective; and time.
Time is especially problematic in disaster reporting because the information flow is fast paced and constantly shifting. Thus, as you pointed out, early reports include incorrect terms that (usually) disappear as the story develops.
In the case of Black Forest Fire, early reports may have (I did not check) stated it was one of the “largest” fires rather than just “worst.” Recent reports have clarified it as the “worst.”
Does that help?