Is Climate Change Making Flooding Worse? - Stormy Data Trumps Fake News on Extreme Weather Trends and Flooding

From the Toronto Star: "Once, when he [Environment Canada's Dave Phillips] offhandedly uttered the words “storm porn” in a pre-interview, a TV reporter built a whole segment around the phrase, because there is only one thing editors and the public crave more than a weather story or a sex story, and that is a sexy weather story." link

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"Stormy Data" is in the news almost daily - the media is obsessed with stories about big rain events and flooding - but sometimes the media is full of "weather porn", i.e., sensational stories and video clips that skew the reality behind severe flooding events. Certainly flooding is a critically important issue across Canada that needs careful and sustained attention to make improvements. But the focus on changing weather as the cause is often incorrect, and the tendency to point to climate change as the cause is equally wrong... Fake News. Fake News! Confused Media!

This post talks about storm porn (sometimes used in insurance marketing), flood loss trends in Canada and the causes, and a history of flooding in the Toronto area that suggests flood events and road/bridge washouts were more frequent in the past before modern floodplain management and design practices. That is good news that Best Practices can reduce flood risk over time!

On Weather - More Extreme? No. Its Storm Porn

Almost 30 years ago we has a cable weather channel that was had simple weather forecasts on the 'tube' (The Weather Network History). Today The Weather Network gives us:

"Force of Nature - (Featured every 20 minutes on the 3's, a show-reel of significant weather making headlines around the world), and Force of Nature Extended segment where a news reporter gives an in-depth description of the footage shown."

and "Storm-Hunters - weekends at 7 and 10pm." and "Angry Planet".... - I call this "storm porn", or "weather porn".

And no fallen limb or large puddle escapes weather reporting. Reporters know to go to the underpasses because they flood in extreme weather ... just like they are designed to - but there is no capacity in weather reporting or mainstream media to even remotely consider these design facts. It is better for business to sensationalize the events. What is better for science and public policy however?

But storms are not bigger or more frequent, or more sever today than they used to be - Environment and Climate Change Canada's Engineering Climate Datasets (Version 2.3) show this, despite what the insurance industry has stated (unfortunately by mixing up predictions with observations, theory with facts, annual precipitation totals with short-duration rain bursts):



Intact Financial Weather Frequency Shift
Intact Financial video promotes disproved 40 year to 6
year weather shift (Telling the Weather Story).
The insurance industry does not properly consider storm/weather data that engineers rely on to assess flood risks and continues to state that "In Canada, weather events that used to occur every forty years are now happening every six years in some regions"  as in this video on their web site/blog. That statement about more frequent weather has been shown to be a 'made-up', theoretical bell-curve shift and not actually real data.




On Flood Causes - Many Factors

Flood incidents are caused by many factors. For example, high risk, historical land use planning:
  1. Gatineau 2017 flooding was due primarily to having 75% of buildings in the 1-in-20 year flood plain, a high risk zone that has a 5% chance of flooding every year.
  2. Toronto Island 2017 flooding was due primarily to not completing the buy-outs of the remaining high risk properties.
Or sometimes operational decisions (mistakes) result in flood incidents. The 2013 GO Train flood is a clear example of known floods risks and inadequate operational care - deeper flooding happened regularly at the stranded train site (even just 6 weeks before), and happened over the span of the line's operation, dating back to the early 1980's. But no operational procedures were in place to check water levels or stop trains from entering the floodplain. When the last train was stranded on July 8, 2013, the Don River Watershed did not receive record rain at all and the river flow was a less than a frequent 1-in-5 year flow rate, something with a 20% chance to occur every year. 

Or sometimes stuff was just built kinda small back in the day. That's right. Infrastructure is just like cars or anything else and used to be built to a lower standard of performance - cars did not have seatbelts or anti-lock brakes and guzzled gas in the 1950's. Similarly, sewer and drainage systems in the 1950's were prone to excess wet weather flow inflow and infiltration (I&I) stresses, inadequate overland flow planning/design, and no river flood hazard mapping or land use regulation.

Or the cumulative effect of urbanization and intensification over a century in urban areas aggravates the issues associated with the factors above. Same old rain results in more flooding.

How many times do we have to say it? "There has been No Collusion between storm frequency and flood frequency". OK, we meant "No Causation", but you get the message.

On Flood Damages / Losses

Damages need to be mitigated. I charted out a Best Practices approach for identifying and mitigating flood risks holistically from 'flood plain to floor drain', looking at riverine, storm and sanitary/wastewater systems in this blog post.

Insured and uninsured losses from catastrophic and relevant events in Canada are charted by Munich RE. These flood losses include categories of hydrologic events and meteorologic events (hurricanes) that are normalized by inflation and growth in GDP to provide an indication of trends over time. The chart below shows flood losses between 1980 and 2017 in Canada:
Canadian Flood Damage Trends Insurance Losses
Canadian Catastrophic and Relevant Event "Flood" Losses, Inflation and Growth Adjusted for Hydrological and Meteorological Events in USD - Prepared by Munich RE NatCatSERVICE.
Losses are creeping up. We do have to address flood risks.

On Flood Frequency - New Normal? Or Old Extremes?

We have a tendency to forget the past. Its not well documented or easy to find.  So this should help.

The Toronto and Region Conservation Authority has documented past flooding in its jurisdiction showing flooding back to 1804 in this undated document called "A History of Flooding in the Metropolitan Toronto and Region Watersheds":

Link to full report.

The report acknowledges that prior to 1850, records of flooding are limited and suggests that many have been lost -  those that survived are in letters and diaries, and do not give a complete picture of past flooding risks.

This is noted in the excerpt below:



Some nice take-aways:

We build better today: "Over the years, road bridges became higher and stronger in response to the changing type and volume of traffic that they were required to carry. Consequently, reports of bridges descruction became rarer over time."

We keep better records today: "... newspapers and other sources tended to record only the most severe events, particularly in areas which flooded almost every spring."

Seems we used to flood A LOT in the past: The number of flood events documented by watershed and tributary/site are listed below. Often small bridges were destroyed but are not listed below. Where major road bridge's were damage and had to be replaced, or where roads washed-out, those events are noted below as "Notable Events". Mill destruction was frequent but is not noted:

Etobicoke Creek Watershed
- Long Branch - 1930 to 1954 - 9 flood events (7 in the spring)
- Brampton - 1854 to 1974 - 22 flood events (13 in the spring)
- Highway 7 at East Branch - 1968 - 1 flood event
- Tributary near Dixie Road and Dundas Street - 1974 - 1 flood event

Total Number of Documented Flood Events = 33
Notable Road and Bridge Destruction Events: 1
- Brampton April 7, 2012 "severe damage to roads, bridges, buildings"

Mimico Creek
- "No flood records have been kept..."
- 2 floods are listed, in 1850 and 1954

Total Number of Documented Flood Events 2

Humber River
- Bloor Street Bridge - 1850 to 1954 - 7 flood events
- Lambton Mills - 10 flood events (5 in the spring)
- Eglinton Flats - 1804 to 1954 - 10 flood events (5 in the spring)
- Weston - 1842 to 1954 - 10 flood events (7 in the spring)
- Albion Road Bridge - 1850 to 1954 - 6 flood events (4 in the spring, Feb-May)
- Thistletown -1878 to 1954 - 4 flood events (2 in the spring)
- Gristmill, Holm, Cord - 1850 to 1893 - 4 flood events (2 in the spring)
- Humber Summit, Rowntree's Mill - 1850 to 1893 - 5 flood events (4 for mill and 1 for subsequent cottages)
- Sawmill J. Brown - 1850 to 1893 - 4 flood events
- Woodbridge - 1878 to 1961 - 19 flood events (13 in the spring)
- Mills on Main Branch - 1850 to 1925 - 6 flood events (5 in the spring)
- Bolton - 1850 to 1972 - 22 flood events (18 in the spring)
- Mills on the Upper Humber River - 1850 to 1909 - 4 flood events (3 in the spring)

Total Number of Documented Flood Events = 111
Notable Road and Bridge Destruction Events5
- Weston, October 15-16, 1954, "Lawrence Avenue Bridge destroyed"
- Eglinton Flats, June 3, 1947. "roads washed out, buildings flooded"
- Humber River, Bloor Street Bridge, Spring 1916 "completely washed out"
- Woodbridge, August 5, 1882 "approaches to bridge on main road washed out"
- Woodbridge, January 13, 1937 "roads flooded and some washed out"

Black Creek
- Floodplain near Mt. Dennis - 1878 to 1954 - 5 flood events (3 in the spring)
- Maple Leaf Drive Area - April 5, 1951 - 1 flood event (in spring)
- Tributary - March 12, 1959 - 1 flood event (in spring)

Total Number of Documented Flood Events7
Notable Road and Bridge Destruction Events2
- Near Mt. Dennis, September 13, 1878, "railroad bridge and bridge on Weston Road destroyed"
- Near Mt. Dennis, May 14, 1893, "bridges destroyed"

Don River
- Lower Don - 1804 to 1954 - 19 flood events (15 in the spring)
- Riverdale Flats - 1804 to 1970 - 19 flood events (15 in the spring)
- Mills Taylor Family - 1850 to 1902 - 5 flood events (4 in spring)
- Mills on Lower East Branch - 1850 to 1902 - 5 flood events (4 in spring)
- Sheppard Avenue Bridge - October 15-16, 1954 - 1 flood event
- Cummer Avenue Bridge - February 11, 1965 - 1 flood event (in spring)
- Gristmills - 1850 to 1881 - 4 flood events (3 in the spring)
- Thornhill - 1850 to 1975 - 11 flood events (9 in the spring) - 11 listed, report cites 12
- Mills and Small Dams, 1850 to 1881, 4 flood events (3 in the spring)
- Yonge Street at Highway 7, 1943 to 1975, 5 flood events (4 in the spring)
- Highway 7 Bridge, 1943 and 1950, 2 flood events (in the spring)
- Gristmill, Hosiel, 1835 to 1881, 5 flood events (4 in the spring)
- Bayview Avenue Bridge, 1850 to 1954, 4 flood events (2 in the spring)
- Hogg's Hollow, 1850 to 1954, 6 flood events (4 in the spring)
- Gristmill, Boyle, 1850 to 1881, 4 flood events (3 in the spring)
- Bathurst Street Bridge, October 15-16, 1954 - 1 flood event
- Mills on West Branch, 1850 to 1881, 4 flood events (3 in the spring)
- Highway 7 Bridge, 1943 to 1975, 4 flood events (3 in the spring)
- CNR Bridge Near Concord, 1878 to 1954, 3 flood events (1 in the spring)
- Small Dam, Lamer, 1850 to 1881, 4 flood events (3 in the spring)

Total Number of Documented Flood Events 111
Notable Road and Bridge Destruction Events13
- Lower Don, April 5, 1850, "Queen Street bridge destroyed, as well as Kingston Road bridge"
- Lower Don, September 13, 1878, "bridges destroyed at Gerrard Street, Queen Street, Kingston Road, as well as many smaller ones"
- Lower Don, February 28, 1902, "roads washed out"
- Sheppard Avenue Bridge (Sheppard Avenue and Leslie) , October 15-16, 1954, "Destroyed during Hurricane Hazel"
- Thornhill, April 5, 1850, "100 feet of Yonge Street washed out"
- Thornhill, spring 1943, "Yonge street washed out in several places"
- Bayview Avenue Bridge, April 5, 1850, "destroyed"
- Bayview Avenue Bridge, September 13, 1878, "destroyed"
- Bayview Avenue Bridge, October 15-16, 1954, "destroyed"
- Hogg's Hollow, April 5, 1850, "approaches to Yonge Street bridge washed out, bridge isolated"
- Hogg's Hollow, October 15-16, 1954, "Yonge Street bridge washed out"
- Bathurst Street Bridge, October 15-16, 1954, "Destroyed"
- CNR Bridge Near Concord, September 13, 1878, March 10-11, 1936, and  October 15-16, 1954, "The railroad was washed out"

Highland Creek
- Cottages and Highland Creek Drive, 1936 to 1977, 24 flood events (20 in the spring)
- Gristmill, Helliwell, 1869 to 1878, 2 flood events (1 in the spring)
- Highway 2 or Kingston Road Bridge, 14 flood events (12 in the spring)
- Sawmill, 1869 to 1878, 2 flood events (1 in the spring)
- Cottages at "The Willows", 16 flood events (14 in the spring)
- Scarborough Golf and Country Club, 1950 to 1977, 19 flood events (16 in the spring)
- Sawmill, 1869 to 1878, 2 flood events (1 in the spring)
- Military Trail Bridge, 1948 to 1977, 19 flood events (15 in the spring)
- Sawmill, 1869 to 1878, 2 flood events (1 in the spring)

Total Number of Documented Flood Events100
Notable Road and Bridge Destruction Events4
- Cottages at "The Willows", February 15, 1949, "roads washed out"
- Cottages at "The Willows", July 4, 1951, "roads washed out"
- Cottages at "The Willows", October 15-16, 1954, "roads, bridge near present Lawrence Avenue washed out"
- Military Trail Bridge,  August 27-28, 1956, "bridge destroyed"

Rouge River
- CNR Bridge, April 10, 1973, 1 flood event in spring
- Highway 2 of Kingston Road Bridge, 1878 to 1956, 5 flood events (3 in the spring)
- Caper Valley Ski Hill, February 2-3, 1978 , 1 flood event in spring
- Meadowvale Avenue Bridge, October 15-16, 1954, 1 flood event
- Mills, 1878 to 1929, 3 flood events (2 in the spring)
- CPR Bridge, October 15-16, 1954, 1 flood event
- Mills below Markham, 1878 to 1929, 3 flood events (2 in the spring)
- Markham, 1837 to 1973, 7 flood events (4 in the spring)
- Unionville, 1878 to 1973, 6 flood events (3 in the spring)
- Mills and Dams, 1878 to 1929, 3 flood events (2 in the spring)
- CNR Tracks, July 19, 1944, 1 flood event
- Mills, 1878 to 1929, 3 flood events (2 in the spring)
- Rouge Valley Inn, October 15-16, 1954, 1 flood event
- Mills on the Little Rouge, 1878 to 1929, 3 flood events (2 in the spring)
- Con.9 Markham Township, 2 flood events (2 in the spring)
- CNR Bridge, 1947 to 1954, 2 flood events
- Mills and Small Dams, 1878 to 1927, 3 flood events (1 in the spring)

Total Number of Documented Flood Events46
Notable Road and Bridge Destruction Events6
- Markham, May 16, 1937, "bridge washed-out (on present Hwy. 7)"
- Markham, October 15-16, 1954, 'town "marooned" by Hwy. 7 washouts on both east and west sides'
- Unionville, October 15-16, 1954, "Main Street washed out north of Hwy. 7"
- CNR Tracks, July 19, 1944, "The tracks were washed out"
- CNR Bridge, August 18, 1947, "Washed out"
- CNR Bridge, October 15-16, 1954, "Washed out" "passenger train partially derailed"

Duffin Creek
- Gristmill, 1878 to 1919, 3 flood events (1 in the spring)
- Pickering Village and Cottages on Riverside Drive, 27 floods (24 in the spring)
- Mills on West Branch, 1878 to 1890, 2 flood events
- Whitevale, 1878 to 1950, 5 events (3 in the spring)
- Green River, 1878 to 1954, 6 events (3 in the spring)
- Mills between Stouffville and Green River, 1878 to 1919, 3 flood events (1 in the spring)
- Stouffville, 1878 to 1972, 10 flood events, (7 in the spring)
- Mills and Small Dams, 1878 to 1919, 3 flood events (1 in the spring)
- Greenwood, 1878 to 1956, 7 flood events (4 in the spring)
- Mills on East Branch, 1878 to 1919, 3 flood events (1 in the spring)

Total Number of Documented Flood Events = 69

Grand Totals:
Total Number of Documented Flood Events = 379
Notable Road and Bridge Destruction Events31

So yes, we have always had many floods in the past and many road, bridge and rail washouts too. And urban areas have expanded considerably since 1804, meaning more places to experience high rainfall and more runoff (before we started to practice better stormwater management quantity control). While the loss of Finch Avenue during the August 19, 2005 storm was significant, we have not had any major road or bridge washouts since, only Military Trail Bridge, August 27-28, 1956 which it is noted "has not been redesigned and remains low and vulnerable to flooding". So despite high runoff stresses and more and more crossings, the loss of roads and railways has not been an issue. This suggests that today's floodplain management and hydraulic structure (i.e., bridge and culvert) practices are largely effective as well, resulting in overall resilient infrastructure.

The TRCA flood history report notes wet cellars or basements for only a couple of the nearly 400 events. That is in contrast with today when it is basement flood damages that are driving flood losses in southern Ontario, not riverine flooding.

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Interesting comment on land use planning practices:
- in Hogg's Hollow, "All of the houses flooded during Hurricane Hazel remain in the floodplain, and several more have been built" ... obviously this just adds to old risk
- in The Willows, "The cottages at The Willows which survived Hurricane Hazel were removed shortly afterwards, and the valley is now parkland" ... and this is the best way to remove risk in the highest risk zones


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