Suppose you know for a fact that this place has never experienced such an an event like this over the last x years with x a large number. Furthermore you have strong evidence the Earth is warming. Then this happens. Such an observation can be significant. It depends on the situation. I don’t know if this event qualifies. I don’t know enough but someone who studies the issue made the tweet. To his trained eye this was noteworthy. Not proof but noteworthy.