Travis Schlepp
Thu, November 9, 2023
People stand near a sinkhole caused from storms in San Diego, California on January 7, 2016. (Getty Images)
New analysis from NASA shows that major flooding in cities along the West Coast could become a serious problem if a strong El Niño develops this winter, which is widely expected.
NASA’s sea level change science team analyzed data and determined that an increase in high-tide flooding could swamp roads and spill into low-lying buildings if the periodic climate phenomenon has a prolonged stay in the western U.S.
El Niño happens every few years and is characterized by sea levels that are higher than normal and above average temperatures in the Pacific along the equator.
This year, a particularly strong El Niño could result in “ten-year flood events” in major cities, including Seattle and San Diego, NASA warns. In South America, Ecuador could see up to three of these same flood events.
Even more alarming than the risk of devastating floods this year, scientists caution that these natural disasters could soon become commonplace.
Currently, these historic flood events are unlikely to happen during non-El Niño years, NASA says, but that could change by the 2030s due to rising sea levels and climate change. These cities could experience these 10-year floods annually, with or without El Niño NASA says.
“I’m a little surprised that the analysis found these 10-year events could become commonplace so quickly,” said Phil Thompson, an oceanographer at the University of Hawaii and a member of NASA’s sea level change science team. “I would have thought maybe by the 2040s or 2050s.”
A ten-year flood is an event that has a 1 in 10 chance of occurring in any given year and is a measure of how high local sea levels can rise.
“Ten-year floods can result in what the National Oceanic and Atmospheric Administration classifies as moderate flooding, with some inundation of roads and buildings, and the possible need to evacuate people or move belongings to higher ground,” NASA said.
NASA says the extent of flooding in specific cities depends on multiple factors, including a region’s terrain and the location of homes and infrastructure near the ocean.
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Because water expands as it warms, sea levels tend to be higher in places with warmer water. Sea levels are rising due to the overall warming of the planet due to the heating of the earth’s atmosphere and the melting of ice sheets and shelves.
These rising temperatures have already increased the total number of high-tide flooding days that cities along the coast experience every year. Those flooding risks are compounded by storm surges and weather events like El Niño.
El Nino
“As climate change accelerates, some cities will see flooding five to 10 times more often,” said Nadya Vinogradova Shiffer, of NASA’s Surface Water and Ocean Topography mission. “SWOT will keep watch on these changes to ensure coastal communities are not caught off guard.”
NASA monitors sea levels through various missions and initiatives in hopes of collecting enough data to help legislators and local leaders prepare their communities for rising sea levels, which are almost assured to continue to be a problem in the coming decades.
To read more about NASA’s sea level monitoring studies, click here.
El Niño could unleash several '10-year flood events' this winter in cities such as Seattle and San Diego
Ben Turner
Fri, November 10, 2023
Giant waves batter Santa Cruz Lighthouse point during the 2018-2019 El Niño event.
A strong El Niño could cause more floods across cities along the western coasts of the Americas this year, swamping roads and inundating buildings, a NASA analysis warns.
This year's El Niño — a warming of surface temperatures from the Central to East Pacific Ocean — could unleash up to five "10-year flood events" this winter in cities such as Seattle and San Diego.
Ten-year floods (those that have a 1-in-10 chance of occurring in any given year) lead to moderate flooding, according to the National Oceanic and Atmospheric Administration, causing exposed roads and buildings to be partially inundated and prompting limited evacuations. There is a 55% chance of El Niño being at least “strong” and a 35% chance of it being "historically strong" this November-to-January season, the U.S. Climate Prediction Center (CPC) said.
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And by the 2030s, climate change and rising sea levels could cause similar floods along the West Coast each year without El Niño, the researchers said.
"I'm a little surprised that the analysis found these 10-year events could become commonplace so quickly," Phil Thompson, an oceanographer at the University of Hawaii at Mānoa and a scientist on NASA's sea-level-change science team, said in a statement.
The El Niño Southern Oscillation occurs every two to seven years and is a natural shift in sea surface temperatures that causes equatorial trade winds, which tend to blow water east to west, to weaken or reverse, causing warm water to flow eastward. This causes global temperatures to increase by about 0.36 degrees Fahrenheit (0.2 degrees Celsius), according to the World Meteorological Organization.
The effects of an El Niño event, which typically last' nine months to two years, are global. The current El Niño, which began in June 2023 and is expected to last until at least April 2024, has already paired with climate change to make 2023 the hottest year on record, causing record droughts across East Africa, Indonesia, Australia and the Americas.
And the biggest effects are likely still to come, given that the strongest effects tend to happen between January and March.
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To investigate how the oscillation is affecting this year's sea levels, NASA used the Surface Water and Ocean Topography (SWOT) and Sentinel-6 Michael Freilich satellites to gauge the height of the ocean before and after this year's El Niño.
The coming flooding is a harbinger of the effects of rising sea levels.
"As climate change accelerates, some cities will see flooding five to 10 times more often," said Nadya Vinogradova Shiffer, a SWOT program scientist and the director of the ocean physics program at NASA.
By monitoring sea surface temperatures, programs like SWOT can help planners prepare ocean defenses and evacuation plans, the researchers said.
El Niño turns strong and still growing as winter fast approaches
Dennis Mersereau
Fri, November 10, 2023
The Pacific Ocean continues running a fever as the northern hemisphere heads into the winter months, and forecasters see the chance for this El Niño pattern to grow even stronger in the weeks to come.
NOAA’s Climate Prediction Center (CPC) issued an El Niño advisory in its monthly update on Thursday, a formality that makes official what we’ve long known—El Niño is here, it’s strong, and it could affect our winter weather.
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El Niño is officially here and growing stronger
We’re on the lookout for potential shifts in winter weather patterns across North America in the weeks ahead as El Niño strengthens in the eastern half of the Pacific Ocean.
Water temperatures in the equatorial Pacific Ocean west of South America have been consistently warmer than normal since the early spring, with a period of steady warming through the summer.
Global sea surface temperatures November 2023
A spell of abnormally warm waters is considered an El Niño when sea surface temperatures are consistently 0.5°C above normal for about seven consecutive months. Anomalies of 1.0°C represent a moderate El Niño, while a strong event features temperatures at least 1.5°C above normal.
Average sea surface temperatures across a critical section of the Pacific are coming in around 1.7°C above average, the CPC said this week, which meets the criteria for a strong El Niño.
Given that this pattern started in the late spring, October's warmth satisfied the time duration required to graduate from a "likely" El Niño to a full-blown event that's ongoing as we move into winter.
This warmth extends more than a hundred metres below the surface, as well, which reinforces the staying power of this event into the first half of 2024.
Experts see continuing odds of a “historically strong” El Niño this season
Greater temperature anomalies signify a stronger El Niño, which may have greater and farther-reaching impacts on global weather patterns.
RELATED: A ‘historically strong’ El Niño is possible heading into winter
Forecasters with the CPC give a 35 percent chance of this El Niño growing “historically strong,” with average temperature anomalies of 2.0°C or warmer. This change represents a slight uptick in the odds of a high-end El Niño compared to the agency’s update in October.
NOAA El Niño Forecast November 2023
Since 1950, only three winters have seen average temperatures in this part of the Pacific rise more than two degrees above normal: 1982-83; 1997-98; and 2015-16. All three of those seasons saw highly impactful shifts in weather patterns around the world.
What could this mean for folks across Canada?
“Past data indicates that El Niño winters tend to be relatively mild across the country, particularly during strong El Niño events like the one anticipated for this winter,” wrote Dr. Doug Gillham in The Weather Network’s look-ahead to what El Niño could portend for our upcoming winter.
Not all El Niño winters are the same. While many of them follow the same patterns, each one has its own personality of sorts.
Some complicating factors will likely make this winter unique, including a far-reaching warmth across the Pacific, as well as the exceptional warmth that remains present throughout much of the Atlantic Ocean.
Dr. Gillham noted that we’ve still seen impactful winter storms even during those milder El Niño winters: “Even mild winters have a risk for impactful winter weather, as demonstrated by the destructive ice storm that struck southern Quebec and eastern Ontario during the powerful El Niño of 1997-98.”
Stay tuned for The Weather Network’s official winter outlook coming out on Wednesday, November 29, and check back frequently throughout the month as forecasters monitor how these pattern changes will affect conditions in your community.
WATCH: How El Niño could affect Canada's winter weather
Click here to view the video
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