Most unusual/strangest hurricane seasons?

[snowpocalypse]

Maybe someone mentioned it already, but what was the least active season on record (ACE and/or named storms)?

As an aside, here is an interesting read suggesting correlation between volcanic events and a reduction in TC activity.
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2011JD016716

[ElectricStorm]

Maybe someone mentioned it already, but what was the least active season on record (ACE and/or named storms)?

As an aside, here is an interesting read suggesting correlation between volcanic events and a reduction in TC activity.
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2011JD016716

1914, one tropical storm

[Ryxn]

Sorta off-topic but I think climatologically speaking, the Atlantic hurricane season should begin its calendar year either March 1st or 10th (instead of January 1st) and end February 28/29th or March 9th (instead of December 31st) to the peak being September 10th. I think the March 1st start is less confusing. Or maybe make it a March 15th calendar start. In my opinion, Hurricane Pali of the 2016 Pacific Hurricane Season has more to do with the 2015 season than the 2016 one as ocean temperatures hit their lowest in late-February.

This is why I consider Hurricane Alex of 2016 that much more of a freak storm because it essentially formed during the extended 2015 Atlantic Hurricane Season which had an El Niño and had ZERO influence from the 2016-17 La Niña. Just my 2 cents.

In my opnion the 2015(-16) Pacific Hurricane Season ended with Category 2 Hurricane Pali

Cheers!

[Shell Mound]

According to climatology for the period 1981–2010, roughly three-fourths of ACE is generated by September 25 during an average season. Typically “hyperactive” seasons generate an average annual ACE index of more than 153. So the typical “hyperactive” season sees an ACE value of at least 111 by September 25. So far 2020 has featured an ACE value of 105 to date, according to the preliminary best track (ATCF). One long-lived MH in the W Caribbean during the month of October may be sufficient for 2020 to approach the “average” annual ACE observed in “hyperactive” years. So, when adjusting for the fact that standards for classification have changed since 2005, and therefore previous “hyperactive” seasons, when judged by the same criteria, may have well featured many more NS than documented, then 2020 perhaps isn’t so unusually “bearish” vs. other “hyperactive” seasons after all.

[Hammy]

Expanding on what I wrote for 1967, the whole 14-year period from 1967 to 1981 featured an unusual amount of tropical depressions that failed to attain tropical storm status with the exceptions of 1969 and 1980. The trend dies down in the 80s as seen.

Below is the number of tropical depressions per year that did not strengthen to tropical storms. Bolded are years with more than 5 systems below tropical storm strength.

1966 and earlier: All 5 or less with the exceptions of 1956 (6 TDs), 1954 (7), 1944 (7), 1938 (6), and 1922 (9)
1966: 2
1967: 21
1968: 6
1969: 2
1970: 8
1971: 9
1972: 12
1973: 16
1974: 9
1975: 14
1976: 11
1977: 10
1978: 12
1979: 17
1980: 5
1981: 10
1982: 3
1983: 3
1984: 7
1985: 3
1986: 4
1987: 7
1988: 7
1989: 4
1990: 2
1990 onward: All 5 or less

There were a lot of systems in the 1960s and 70s that are disturbances that (for some reason) are listed in the track archive, and are listed as low, rather than depression. I've just finished wrapping up finding all the disturbances and what was numbered as what, this does not include systems listed as disturbances that I've determined were likely depressions:

1966: 2 (2, 7)
1967: 15 (1 2 3 4 5 10 11 13 15 16 18 19 20 21 23)
1968: 14 (1 2 4 7 8 9 11 12 13 14 16 18 19 21)
1969: 24 (1-12; 14 15 19 20 21 23 26 28 29 31 34 36)
1970: 11 (2 3 4 5 7 9 10 12 14 15 19)
1971: 10 (2 3 5 8 11 15 16 18 19 22)
1972: 9 (3-9; 12 14 17)
1973: 8 (1 2 4 5 7 11 13 17)
1974: 4 (1 4 9 11)
1975: 8 (3 4 6 7 11 12 14 15)
1976: 2 (10 plus one unnumbered post-season additions listed in BT)
1977: 3 (4 6 11)
1978: 9 (4 8 9 12 plus five unnumbered post-season additions listed in BT)
1979: 9 (1 4 6 8 13 14 15 plus three unnumbered post-season additions listed in BT)
1980: 6 (1 4 6 14 plus two unnumbered post-season additions listed in BT)
1981: 11 (2 4 7 8 13 15 plus five unnumbered post-season additions listed in BT)
1982: 3 (2 6 7)
1983: 3 (1 2 6)
1984: 7 (1 2 3 7 plus three unnumbered post-season additions listed in BT)
1985: 3 (6 13 plus one unnumbered post-season additions listed in BT)
1986: 4 (3 5 6 plus one unnumbered post-season additions listed in BT)
1987: 7 (1 4 6 8 9 11 14)
1988: 7 (1 4 5 6 10 15 18)
1989: 4 (1 6 9 13)

In 1974 there seemed to be a change in criteria for depressions, and I imagine some later high years (1978, 79, 81, 84, 87, 88) there could be some that will be declared tropical storms once the reanalysis arrives, along with several from 1966-73 as well.

1975 somehow has one more system than makes sense for operational depression numbering, with two systems between TD4 and TD6.

[Shell Mound]

“Most unusual/strangest hurricane seasons?”

Uhh...2020?

[Hurricane Mike]

Hurricane Seasons seem stranger lately, especially with the "late season" activity.

When I was tracking hurricanes in the 1990s, I seem to remember many August and September storms. Now the bulk of activity comes in October or even November. 2012: Sandy. 2015: Joaquin. 2016: Matthew, Nicole, Otto. 2018: Michael, a Cat 5 U.S. landfall on OCTOBER 10TH?! 2020: Delta, Zeta, Eta, Iota. All were October/November hurricanes.

I guess I just remember storms being more prolific in August and September. I have also noticed here in the Midwest that our seasons seem much shorter, and we don't have much of a spring or fall. We generally go from snow to hot, and then hot to snow. I also notice things like blackberry bushes that were extremely prevalent as a kid 25 years ago now being almost completely non-existent.

I'm not a climate change guy, but it is curious. I guess 2010, 2011, 2017 and 2019 all had normal time frame storms like Earl, Igor, Irene, Harvey, Irma and Dorian. But these extreme constant Category 5 storms are making me curious. We didn't have any Category 5 hurricanes between 1998 and 2003, or between 2007 and 2016. Now we've had so many in just four years. Perhaps it's all coincidence.

[ElectricStorm]

Hurricane Seasons seem stranger lately, especially with the "late season" activity.

When I was tracking hurricanes in the 1990s, I seem to remember many August and September storms. Now the bulk of activity comes in October or even November. 2012: Sandy. 2015: Joaquin. 2016: Matthew, Nicole, Otto. 2018: Michael, a Cat 5 U.S. landfall on OCTOBER 10TH?! 2020: Delta, Zeta, Eta, Iota. All were October/November hurricanes.

I guess I just remember storms being more prolific in August and September. I have also noticed here in the Midwest that our seasons seem much shorter, and we don't have much of a spring or fall. We generally go from snow to hot, and then hot to snow. I also notice things like blackberry bushes that were extremely prevalent as a kid 25 years ago now being almost completely non-existent.

I'm not a climate change guy, but it is curious. I guess 2010, 2011, 2017 and 2019 all had normal time frame storms like Earl, Igor, Irene, Harvey, Irma and Dorian. But these extreme constant Category 5 storms are making me curious. We didn't have any Category 5 hurricanes between 1998 and 2003, or between 2007 and 2016. Now we've had so many in just four years. Perhaps it's all coincidence.

Honestly I just think it's one of those things where every season is different in its own way. I've only been tracking the tropics since 2015, so I never experienced tracking the the storms of the 90s and early 2000s but I have certainly went back and have researched many of them. To me, every season has something that it is "known" for. For me, 2015 is known for producing a near Cat 5 in a super Niño. 2016 and 2020 are known for having a big backside of the season. 2017 is known for its large number of intense CV storms, as well as being ultra-destructive and deadly. 2018 had a large number of subtropical cyclones, as well as intense Florence and Micheal. 2019 also had a large number of systems in the Subtropics, but also produced 2 cat 5s. So to me, I just think it's just each season being different in its own way. IMO

[Shell Mound]

Hurricane Seasons seem stranger lately, especially with the "late season" activity.

When I was tracking hurricanes in the 1990s, I seem to remember many August and September storms. Now the bulk of activity comes in October or even November. 2012: Sandy. 2015: Joaquin. 2016: Matthew, Nicole, Otto. 2018: Michael, a Cat 5 U.S. landfall on OCTOBER 10TH?! 2020: Delta, Zeta, Eta, Iota. All were October/November hurricanes.

I guess I just remember storms being more prolific in August and September. I have also noticed here in the Midwest that our seasons seem much shorter, and we don't have much of a spring or fall. I also notice things like blackberry bushes that were extremely prevalent as a kid 25 years ago now being almost completely non-existent.

Maybe the poles are shifting, hence the four seasons begin earlier, end later, and meld together...

[aspen]

Hurricane Seasons seem stranger lately, especially with the "late season" activity.

When I was tracking hurricanes in the 1990s, I seem to remember many August and September storms. Now the bulk of activity comes in October or even November. 2012: Sandy. 2015: Joaquin. 2016: Matthew, Nicole, Otto. 2018: Michael, a Cat 5 U.S. landfall on OCTOBER 10TH?! 2020: Delta, Zeta, Eta, Iota. All were October/November hurricanes.

I guess I just remember storms being more prolific in August and September. I have also noticed here in the Midwest that our seasons seem much shorter, and we don't have much of a spring or fall. We generally go from snow to hot, and then hot to snow. I also notice things like blackberry bushes that were extremely prevalent as a kid 25 years ago now being almost completely non-existent.

I'm not a climate change guy, but it is curious. I guess 2010, 2011, 2017 and 2019 all had normal time frame storms like Earl, Igor, Irene, Harvey, Irma and Dorian. But these extreme constant Category 5 storms are making me curious. We didn't have any Category 5 hurricanes between 1998 and 2003, or between 2007 and 2016. Now we've had so many in just four years. Perhaps it's all coincidence.

I think the ridiculous amount of October and November hurricanes this year was due to a couple of things:
1.) the Atlantic was in a very favorable base state for the entire year, but other conditions weren’t always able to match up with it
2.) this year’s La Niña didn’t form until mid-September, and didn’t really kick into full gear until October. That meant true La Niña conditions missed the peak of Cape Verde season
3.) the unexpected TUTT fueled by Bavi, Maysak, and Haishen prevented the horrifying Cape Verde season everyone was anticipating. If it didn’t exist, storms like Paulette, Rene, and Teddy could’ve become stronger and longer-tracking MDR hurricanes, and this season wouldn’t look so back-loaded

In short, a variety of factors that suppressed MDR activity despite the hyper-favorable base state and developing Niña led to a season with a ton of quantity>quality during the normally more active Cape Verde season, and a ton of quality and quantity during the normally less active October-November time frame. Laura could’ve been this year’s long-tracking super-intense MDR system if it went either a little further north of a little further south — either of which would’ve led to an even more impactful storm. Believe it or not, 2020 could’ve been even worse.

[Hammy]

Hurricane Seasons seem stranger lately, especially with the "late season" activity.

When I was tracking hurricanes in the 1990s, I seem to remember many August and September storms. Now the bulk of activity comes in October or even November. 2012: Sandy. 2015: Joaquin. 2016: Matthew, Nicole, Otto. 2018: Michael, a Cat 5 U.S. landfall on OCTOBER 10TH?! 2020: Delta, Zeta, Eta, Iota. All were October/November hurricanes.

I guess I just remember storms being more prolific in August and September. I have also noticed here in the Midwest that our seasons seem much shorter, and we don't have much of a spring or fall. We generally go from snow to hot, and then hot to snow. I also notice things like blackberry bushes that were extremely prevalent as a kid 25 years ago now being almost completely non-existent.

I'm not a climate change guy, but it is curious. I guess 2010, 2011, 2017 and 2019 all had normal time frame storms like Earl, Igor, Irene, Harvey, Irma and Dorian. But these extreme constant Category 5 storms are making me curious. We didn't have any Category 5 hurricanes between 1998 and 2003, or between 2007 and 2016. Now we've had so many in just four years. Perhaps it's all coincidence.

I think the ridiculous amount of October and November hurricanes this year was due to a couple of things:
1.) the Atlantic was in a very favorable base state for the entire year, but other conditions weren’t always able to match up with it
2.) this year’s La Niña didn’t form until mid-September, and didn’t really kick into full gear until October. That meant true La Niña conditions missed the peak of Cape Verde season
3.) the unexpected TUTT fueled by Bavi, Maysak, and Haishen prevented the horrifying Cape Verde season everyone was anticipating. If it didn’t exist, storms like Paulette, Rene, and Teddy could’ve become stronger and longer-tracking MDR hurricanes, and this season wouldn’t look so back-loaded

In short, a variety of factors that suppressed MDR activity despite the hyper-favorable base state and developing Niña led to a season with a ton of quantity>quality during the normally more active Cape Verde season, and a ton of quality and quantity during the normally less active October-November time frame. Laura could’ve been this year’s long-tracking super-intense MDR system if it went either a little further north of a little further south — either of which would’ve led to an even more impactful storm. Believe it or not, 2020 could’ve been even worse.

The monsoon trough being quite a bit further west and north than normal was also a major contributor here. Rene actually had quite favorable upper wind conditions during the early and middle portion of its lifespan, but was done in by cooler water and drier air given it's latitude that far east. Similar to Paulette, the trough flung the incipient disturbance much farther north than you'd expect that far east and right into the TUTT and cooler SSTs. No doubt this also significantly delayed initial development.

[MarioProtVI]

Hurricane Seasons seem stranger lately, especially with the "late season" activity.

When I was tracking hurricanes in the 1990s, I seem to remember many August and September storms. Now the bulk of activity comes in October or even November. 2012: Sandy. 2015: Joaquin. 2016: Matthew, Nicole, Otto. 2018: Michael, a Cat 5 U.S. landfall on OCTOBER 10TH?! 2020: Delta, Zeta, Eta, Iota. All were October/November hurricanes.

I guess I just remember storms being more prolific in August and September. I have also noticed here in the Midwest that our seasons seem much shorter, and we don't have much of a spring or fall. We generally go from snow to hot, and then hot to snow. I also notice things like blackberry bushes that were extremely prevalent as a kid 25 years ago now being almost completely non-existent.

I'm not a climate change guy, but it is curious. I guess 2010, 2011, 2017 and 2019 all had normal time frame storms like Earl, Igor, Irene, Harvey, Irma and Dorian. But these extreme constant Category 5 storms are making me curious. We didn't have any Category 5 hurricanes between 1998 and 2003, or between 2007 and 2016. Now we've had so many in just four years. Perhaps it's all coincidence.

I think the ridiculous amount of October and November hurricanes this year was due to a couple of things:
1.) the Atlantic was in a very favorable base state for the entire year, but other conditions weren’t always able to match up with it
2.) this year’s La Niña didn’t form until mid-September, and didn’t really kick into full gear until October. That meant true La Niña conditions missed the peak of Cape Verde season
3.) the unexpected TUTT fueled by Bavi, Maysak, and Haishen prevented the horrifying Cape Verde season everyone was anticipating. If it didn’t exist, storms like Paulette, Rene, and Teddy could’ve become stronger and longer-tracking MDR hurricanes, and this season wouldn’t look so back-loaded

In short, a variety of factors that suppressed MDR activity despite the hyper-favorable base state and developing Niña led to a season with a ton of quantity>quality during the normally more active Cape Verde season, and a ton of quality and quantity during the normally less active October-November time frame. Laura could’ve been this year’s long-tracking super-intense MDR system if it went either a little further north of a little further south — either of which would’ve led to an even more impactful storm. Believe it or not, 2020 could’ve been even worse.

The TUTT believe it or not was actually what caused 2020 to surpass 2005. If the TUTT didn’t exist much of the weaker storms during peak and spin ups like Wilfred, Vicky, etc wouldn’t form because they would’ve been sheared to death by Paulette or Teddy because they would’ve been much stronger. We would’ve ended at Epsilon I think.

[al78]

It has been mentioned but 2007. A strong La Nina, two cat 5's, yet below average seasonal activity and little late season activity which is the opposite of what normally happens during a La Nina season.

2013, most if not all were expecting an active season or at least average, end result, sod all.
2004/5 back to back seasons, very bad for the Gulf offshore industry and the U.S. 2004 saw the powerful storms driven west at low latitude, 2005 was a season on steroids, a cat 4 and a cat 5 in July, wtf?! Then Katrina which is a good aprroximation to the worst case scenario for the Gulf coast.
2020, a season of stark contrast between the first and second half.
2000, a bit like this year, MDR forming storms heading west really struggled and most were sheared apart, the only two which developed into significant hurricanes were the ones which moved swiftly out of the MDR.
2018, quiet until the end of August, then an explosion of activity, plus unusually high activity in the sub-tropics, which put the ACE well into the active threshold despite seasonal forecasts not expecting more than an average season.

There was that season in the 60's I think which had a storm intensify rapidly into a cat 5 with a ridiculously high central pressure, then weaken to a tropical storm 6 hours later before making landfall.

[al78]

I'm not a climate change guy, but it is curious. I guess 2010, 2011, 2017 and 2019 all had normal time frame storms like Earl, Igor, Irene, Harvey, Irma and Dorian. But these extreme constant Category 5 storms are making me curious. We didn't have any Category 5 hurricanes between 1998 and 2003, or between 2007 and 2016. Now we've had so many in just four years. Perhaps it's all coincidence.

To get a cat 5 in the Atlantic requires a lot of favourable things to come together simultaneously, which doesn't happen very often and is largely down to luck. There is a possibility that climate change-related warming of the oceans will load the dice toward more cat 5's in the future, say, what would peak at 130-135 kts now may have peaked at 140 kts if the ocean were half a degree warmer, but you need the dynamic conditions to be aligned with the thermodynamic conditions to get the most powerful storms, and I'm not sure what the projections for the mean atmospheric conditions during peak season are for future climate change.

[Shell Mound]

There was that season in the 60's I think which had a storm intensify rapidly into a cat 5 with a ridiculously high central pressure, then weaken to a tropical storm 6 hours later before making landfall.

That storm was Hurricane Ethel (1960), recently reassessed as a Cat-3, not a Cat-5. 1960 was still noted for Donna, however: ‘cane-force gusts from FL to ME.

[MarioProtVI]

It has been mentioned but 2007. A strong La Nina, two cat 5's, yet below average seasonal activity and little late season activity which is the opposite of what normally happens during a La Nina season.

2013, most if not all were expecting an active season or at least average, end result, sod all.
2004/5 back to back seasons, very bad for the Gulf offshore industry and the U.S. 2004 saw the powerful storms driven west at low latitude, 2005 was a season on steroids, a cat 4 and a cat 5 in July, wtf?! Then Katrina which is a good aprroximation to the worst case scenario for the Gulf coast.
2020, a season of stark contrast between the first and second half.
2000, a bit like this year, MDR forming storms heading west really struggled and most were sheared apart, the only two which developed into significant hurricanes were the ones which moved swiftly out of the MDR.
2018, quiet until the end of August, then an explosion of activity, plus unusually high activity in the sub-tropics, which put the ACE well into the active threshold despite seasonal forecasts not expecting more than an average season.

There was that season in the 60's I think which had a storm intensify rapidly into a cat 5 with a ridiculously high central pressure, then weaken to a tropical storm 6 hours later before making landfall.

I think 2007 was a flop because I think SAL was stronger that year and then September ended up getting clogged with TUTTs which sheared anything in the MDR at peak (Ingrid, Karen, Melissa, etc), and then most of October got wasted because of some enormous gyre that formed in the Caribbean trying to become something and then it ended up just moving inland and sitting for days which practically prevented anything trying to form because of such broad vorticity. I think CSU even wrote a paper on why September-October 2007 was pretty much garbage.

[Hammy]

1979 is another that comes to mind. Early MDR activity with Ana in June and Claudette in July, and then absolutely nothing during August until the last week of the month when things exploded (David, TD8, Elena, and Frederic in about a six day span) and then it just shut off after mid-September.

[GrayLancer18]

2004 Comes into mind. It was expected to be inactive due to a Warm ENSO and nothing formed until literally the beginning of August when the lid comes off and ends with 15 storms, many of them long ranged and 4 that gave Florida the season of its lifetime.

Even weirder one is 1961. Only one C2 storm in July, NOTHING in August but come September and the season ends up with 5 Major Hurricanes, 2 of them Cat5s, Esther and Hattie (had Carla not been downgraded, it could've had THREE Cat5s!)

[InfernoFlameCat]

1914
1 tropical storm
Does it even qualify for a hurricane season without a hurricane

[Ryxn]

I also posted this in the 2020 reflections thread but I think it makes 2020 stick out like a sore thumb...

If no additional tropical cyclones form this year, 2020 will be the ONLY Atlantic Hurricane Season to have a Category 5 storm as its final (last-forming) tropical cyclone. This has never happened before 2020. It almost occurred in 1999 with Lenny but that storm was 5 mph short. 2020 is the first year to end the season with a major hurricane since 2016 (Otto) and one of only 12 seasons (or 14 if you count 1905 and 1932) to do so.

Strongest Final Tropical cyclones of a Season (all Cat. 3+)
*1. Iota, 2020 (160 mph)
2. Lenny, 1999 (155 mph)
3. Five, 1910 (150 mph)
4. Paloma, 2008 (145 mph)
5. Six, 1882 (140 mph)
6. Five, 1855 and Nine, 1867 (125 mph)
7. Five, 1873, Five, 1876, Seven, 1912, Thirteen, 1934 and Otto, 2016 (115 mph)
*Strongest Last-Dissipating Tropical Cyclones
1. Fourteen (Cuba), 1932 (175 mph) (ahead of Iota)
8. Four, 1905 (120 mph)

The 1905 and 1932 seasons had final dissipating storms that were at one point in their lives a major hurricane with 1905's Four and 1932's Fourteen (Cuba November). However, only 1932's last-dissipating storm was a major hurricane (Cat. 4) after the dissipation of the season's penultimate dissipating storm (Fifteen).

2016 is also notable the ONLY season to end its season with 3 CONSECUTIVE tropical cyclones attaining major hurricane status, with a neat and tidy descending order of Category 5, 4, and 3.

What makes 2020's case extra insane is that it attempted a Category 5 two times previous to Iota with Laura and Eta (which may have hit it) and Iota came in mid-November after 30 tropical cyclones and still caused 2020 to round off with a Category 5! Talk about a finale. If you come to think of it, October and November 2020 was quiet the final 2 months with likely 6 hurricanes (with Gamma) and an obscene possible 5 majors (with Zeta). This has also NEVER happened before 2020.

Talk about a wacky year!