An emergency page is not a normal page. The person reading it is stressed, probably on a phone, possibly standing in water. Everything that works on a calm Tuesday afternoon stops working.
One decision, not five
Remove the navigation menu, the service grid, the blog links. An emergency page should offer a phone call and nothing else. Every extra option is one more thing to process.
Big text, high contrast
Shaky hands, bad light, a cracked screen. Make the phone number the largest thing on the page and make sure it is readable at arms length.
Answer "how fast" immediately
The only question that matters is how soon someone arrives. If you can say "within the hour in these areas", say it in the first line. Vague promises lose to a competitor who commits to a number.
Say what to do while they wait
Where the stopcock is, how to cut the power safely, what not to touch. It costs you nothing, it genuinely helps, and it is the kind of page people bookmark and send to a neighbour.