The Surprising Truth About a 100-Year Flood

The surprising thing about 100-year events is that they can happen year after year, not just once every 100 years. That's because the term 100-year event is about chance (probability), not a schedule. It’s a statistical term that means a 100-year event has a 1 in 100 chance of happening each year.

It's One in a Hundred, Every Year

Think about flipping a coin. There's a 50/50 chance of getting heads each time you flip the coin. But you might actually get heads three times in a row. Or 50 times!
Each year, a river may flood or not. The chance of it flooding to a certain height is 1 in 100, or 1%. But the river may have flooded that high three years in a row. Or more!

Thousand Year Event 

Up on the Rouge River in Quebec, just north of the Ottawa River, there is so much flooding right now that it's a 1000-year event. Such a high water level is 10 times less likely to happen than a 100-year flood. Each year on the Rouge River, there is a 1 in 1000 chance that the water will rise this high — a 0.1% chance of it happening.

Figuring Out the Chances

How do we figure out the chances of an event happening? Meteorologists (weather scientists) need at least 10 years of data to math out the chances. The more data they have (say, 30 years’ worth, for example) the more accurate their calculations are. As climate change brings us more and more wacky weather, they’ll have to keep recalculating the chances. What was once a 1000-year event may now be 10 times more likely to happen. New calculations will tell us; and they’ll have to keep redoing those calculations as the data changes.

Not Just for Flooding

The terms 100-year event or 1000-year event can apply to anything: storms, cleaning you room, or having chocolate cake for dinner in the bathtub. Though that last thing might be a 1-millennium event, maybe you can make it happen this year and next.

---

Want to learn more? There’s a thorough but a bit complex explanation on the USGS (“geological service” that studies our planet) website.

Image by Pete Linforth from Pixabay
Story by Adrienne Montgomerie 

This Hour Takes 22 Minutes. Off Your Life.

By L E Carmichael

News.  Sit-Coms.  The Discovery Channel.  The latest "reality" drama.   No matter what you're tuning in to, you might want to turn it off.  According to a new study, television does more than rot your brain: it shortens your life.

A group of Australian scientists collected data from more than 11,000 people over the age of 25.  They compared the number of hours people spent watching TV every day to the number of years people lived.  The results were shocking.

A person who watches 6 hours of TV per day lives, on average, 4.8 years less than a person who watches no TV at all.  Every hour of TV watched after age 25 is associated with a decline in life expectancy of 22 minutes. 

The researchers compared TV viewing time with other risk factors for reduced lifespan.  This is a chart I made, based on data mentioned in the study:

That's right - watching 6 hours of TV per day appears to be as dangerous as lifelong smoking.  And if you're thinking that no one watches 6 hours of TV per day, you're wrong - the average adult in the USA watches about 5 hours a day.  That's 35.5 hours per week spent watching TV.  Or put another way, almost as many hours as a full-time job.

It might be a little soon to go throwing away your remote control.  This study demonstrates a negative correlation - in science-speak, interdependence between two variables.  In other words, as TV-viewing time increases, lifespan decreases.  That doesn't mean that television, in and of itself, is directly responsible for early death.  Correlations are not the same as causes.  Indeed, two correlated variables may in fact be responding to the same underlying-and-as-yet-unidentified cause.

In the case of this study, that cause is most likely sedentary behaviour, also known as too darn much sitting around.  And that sitting isn't just done in front of the tube.  It's at work, in the car, eating at restaurants and typing out emails.

Excuse me.  I have to put my laptop down now, go out, and take a walk.