The relentless rain from Chantal brought on historic flooding of the Eno River, multiple water rescues, road closures, downed trees, tornadoes and power outages in our western counties.

Widespread rain totals of four to eight inches were seen in parts of Moore, Chatham and Orange Counties, while there were pockets of even five to ten inches.

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Most of this fell within a six to twelve hour time frame, making it especially rare.

Using what's called a recurrence interval, we can look at the statistical odds of something this significant happening in any given area.

Chantal's flooding put in perspective
Chantal's flooding put in perspective

When plugging in the rain totals for areas like Pinehurst, Siler City and Chapel Hill, the rain we saw consistently fell into what we'd call a 500-year to 1,000-year flood event.

Sunday's rain was a 500-1,000-year flood in some areas
Sunday's rain was a 500-1,000-year flood in some areas

"How can it be a 500-year or 1,000-year flood event if we saw something similar in 1996?"

I see this question asked whenever this type of flooding occurs. Admittedly, the phrase "500-year to 1,000-year flood" can be misconstrued.

What it means is that - statistically speaking - a flood like that has a 0.2% to 0.1% chance of happening in any given year.

What a 1,000-year flood means vs. what it does not mean
What a 1,000-year flood means vs. what it does not mean

In fact, six inches or more of rain within 24 hours is something that's only happened three times in Orange County. Those three times were during Florence, Fran and Floyd.

Nearly historic rain from Chantal in Orange County
Nearly historic rain from Chantal in Orange County

The Eno River near Durham rose to record-breaking levels, as shown by this picture from Ken Wynne. That sign shows where water levels rose during Fran in 1996.

Ken Wynne - Eno River in Durham
Ken Wynne - Eno River in Durham

It's really just a way to put perspective on the significance and the rarity of a weather event like this.