General Severe Weather Discussion 2018

[tamarack]

35 minutes ago, Ginx snewx said:

https://physicsworld.com/a/trees-break-at-fixed-wind-speed-irrespective-of-size-or-species/

Color me VERY unimpressed.

During storms, there is a critical wind speed, of around 42 m/s (90 mph), at which almost all tree trunks break – irrespective of their size or species – according to a new study done by researchers in France

If this statement intends to say that winds of 90 mph will break nearly all trees, I'd have little argument (while noting that palms, which sometimes withstand stronger winds, are botanically very big grass.)  However, the link seems to infer that all trees break at the same windspeed, and empirical evidence says otherwise.

To explore this further, Virot and his colleagues conducted experiments on horizontal beech rods. While mechanical differences between different tree species are slight, beech was chosen as a wood with average proprieties

So we can toss out all the lumber standards based on species?  There's a good reason why wooden RR ties were made from dense hardwoods like oak and maple, not aspen or basswood.  A test that not only works with limbless "trees" but uses wood from just one species, then applies those results as being the same for all species and to real trees in the forest has little practical validity, IMO.  I'm glad the silviculturist's comments were added.
A facet being used more recently for evaluating windfirmness is height-diameter ratio, that is, total height divided by diameter at 4.5' above ground, the standard for forest inventories in which only one diameter measurement per tree is taken.  (Outside the US, it's 1.4m, essentially the same.)  H:D ratios above 60 point toward lessening windfirmness, and those trees with 70+ have been found to be quite vulnerable.
Taking into consideration that trees nearly triple in diameter for a doubling in their height
Except they don't, other than perhaps as an average, and that differs widely among species - northern white cedar tapers far more rapidly than aspen or pine, and nearly all trees will have far more taper when open-grown than those in a dense stand.

rant over        (But thanks for the link.)

[bobbutts]

Any more info on this tornado?

Quote

 

At noon Wednesday, the National Weather Service confirmed that one tornado funnel reached the ground near Lincoln but apparently did no damage.

 

[Ginx snewx]

6 minutes ago, tamarack said:

Color me VERY unimpressed.

During storms, there is a critical wind speed, of around 42 m/s (90 mph), at which almost all tree trunks break – irrespective of their size or species – according to a new study done by researchers in France

If this statement intends to say that winds of 90 mph will break nearly all trees, I'd have little argument (while noting that palms, which sometimes withstand stronger winds, are botanically very big grass.)  However, the link seems to infer that all trees break at the same windspeed, and empirical evidence says otherwise.

To explore this further, Virot and his colleagues conducted experiments on horizontal beech rods. While mechanical differences between different tree species are slight, beech was chosen as a wood with average proprieties

So we can toss out all the lumber standards based on species?  There's a good reason why wooden RR ties were made from dense hardwoods like oak and maple, not aspen or basswood.  A test that not only works with limbless "trees" but uses wood from just one species, then applies those results as being the same for all species and to real trees in the forest has little practical validity, IMO.  I'm glad the silviculturist's comments were added.
A facet being used more recently for evaluating windfirmness is height-diameter ratio, that is, total height divided by diameter at 4.5' above ground, the standard for forest inventories in which only one diameter measurement per tree is taken.  (Outside the US, it's 1.4m, essentially the same.)  H:D ratios above 60 point toward lessening windfirmness, and those trees with 70+ have been found to be quite vulnerable.
Taking into consideration that trees nearly triple in diameter for a doubling in their height
Except they don't, other than perhaps as an average, and that differs widely among species - northern white cedar tapers far more rapidly than aspen or pine, and nearly all trees will have far more taper when open-grown than those in a dense stand.

rant over        (But thanks for the link.)

Yea I had a ton of questions on that plus trees have health issues and if thats the case why do we see tons more white pine damage down here than healthy oak

[Ginx snewx]

1 minute ago, bobbutts said:

Any more info on this tornado?

 

20 yds and a video showing it hitting a wooded area for a brief minute

[tamarack]

31 minutes ago, Ginx snewx said:

Yea I had a ton of questions on that plus trees have health issues and if thats the case why do we see tons more white pine damage down here than healthy oak

Exactly.  If they had tested, say, Lombardy poplar as well as beech, they might have reached a different conclusion.

[Ginx snewx]

23 minutes ago, tamarack said:

Exactly.  If they had tested, say, Lombardy poplar as well as beech, they might have reached a different conclusion.

using their theory I should hit as well with a pine bat as a maple, think about it

[OceanStWx]

4 hours ago, tamarack said:

Assuming that's a serious comment, I'd find that quite interesting, though I'm still working full time (for about another year) and thus would have limited availability.  An experienced arborist might do just as well, and probably better for tree damage in an urban environment.

Half serious anyway. Right now we only differentiate between hardwood and softwood (and some mets probably don't know the difference) and not by species. Hell if I know if ash or elm breaks first in strong wind.

[OceanStWx]

2 hours ago, bobbutts said:

Any more info on this tornado?

 

Looks like we didn't send anyone out there, so unless we hear about more damage, what you see is what you get. 

[MarkO]

1 hour ago, OceanStWx said:

Looks like we didn't send anyone out there, so unless we hear about more damage, what you see is what you get. 

Any info and/or coordinates of where it touched down?

[OceanStWx]

17 minutes ago, MarkO said:

Any info and/or coordinates of where it touched down?

Beginning Lat/Lon...44.08N / 71.72W

[kdxken]

Was going to hike on up yesterday but after reading the forecast decided on another day. Plenty of folks were headed up however.

[kdxken]

5 hours ago, bobbutts said:

Any more info on this tornado?

 

I was in Lincoln when it came through and didn't see it myself but it was nasty. At the Woodstock Inn the woman next to me had a good video although it hadn't reached the ground. She was Clueless on how to transfer but said she was going to send it to News 9, might be there.

[OceanStWx]

4 minutes ago, kdxken said:

I was in Lincoln when it came through and didn't see it myself but it was nasty. At the Woodstock Inn the woman next to me had a good video although it hadn't reached the ground. She was Clueless on how to transfer but said she was going to send it to News 9, might be there.

Email to [email protected] would work too! 

[MarkO]

1 hour ago, OceanStWx said:

Beginning Lat/Lon...44.08N / 71.72W

Thanks.

Pretty remote area and even though it's only about 1.5 miles west of 93/Rt 3. There's no way of getting there other than what appears to be a path beneath power lines and I'm guessing that would require permission from the power company.

[kdxken]

Video I took across from Loon right before it starting banging.

 

[tamarack]

14 hours ago, OceanStWx said:

Half serious anyway. Right now we only differentiate between hardwood and softwood (and some mets probably don't know the difference) and not by species. Hell if I know if ash or elm breaks first in strong wind.

For those 2 species there's probably little difference - perhaps the elm might go first.  Substitute aspen for either and the difference becomes stark.  Aspen wood is far weaker and it's not only a tall species but one with all its foliage near the top, thus maximizing the wind's leverage.  On my woodlot (and anywhere else I've looked), aspen suffers most from wind when leaves are full, balsam fir when leaves have fallen.

[OceanStWx]

12 hours ago, MarkO said:

Thanks.

Pretty remote area and even though it's only about 1.5 miles west of 93/Rt 3. There's no way of getting there other than what appears to be a path beneath power lines and I'm guessing that would require permission from the power company.

That's probably a heavy estimate of location too. It's tough to tell from the video exactly where it is. It looks likely that it touched down on Wolf Mountain (where there are some hiking trails), but it could also be the ridgeline before Wolf Mountain.

[weatherwiz]

17 hours ago, OceanStWx said:

Half serious anyway. Right now we only differentiate between hardwood and softwood (and some mets probably don't know the difference) and not by species. Hell if I know if ash or elm breaks first in strong wind.

You know what's interesting...after seeing the damage across western CT after the event I started to notice that there seemed to be a striking similarity with regards to the type of trees that were knocked down and which weren't. I don't know anything about tree species and such but my friend from NH does. I wish when he was done for a few weeks I had thought about this b/c I could have mentioned it to him and he could have looked at the trees and such. But it was weird b/c you would have an area of damage and the trees that were down seemed to be a similar species. 

[Damage In Tolland]

And such?

[weatherwiz]

1 minute ago, Damage In Tolland said:

And such?

? 

[HoarfrostHubb]

20 hours ago, Ginx snewx said:

20 yds and a video showing it hitting a wooded area for a brief minute

And they called Blizz's a fakenado...

[dendrite]

25 minutes ago, Damage In Tolland said:

And such?

such = sobriety?

[LongBeachSurfFreak]

5 hours ago, tamarack said:

For those 2 species there's probably little difference - perhaps the elm might go first.  Substitute aspen for either and the difference becomes stark.  Aspen wood is far weaker and it's not only a tall species but one with all its foliage near the top, thus maximizing the wind's leverage.  On my woodlot (and anywhere else I've looked), aspen suffers most from wind when leaves are full, balsam fir when leaves have fallen.

Interesting about the balsam fir.  

I did extensive hiking around Long Island after sandy and determined that species acted different then expected. Oaks received by far the most damage. They tended to fully uproot. I was able to locate several full blow downs in a preserve near my house. 100 mature red and white oaks toppled like dominos. Meanwhile red maple, sweet gum, black gum and tulip right next to them where perfectly fine.

My theory on why the oaks took such a comparable beating is due to their folliage. Oak leaves are very robust and thus tended to stay on the tree during the many hours of strong winds leading up to the period of extreme winds that caused the blow downs. Most of the other species had a good amount of their folliage stripped earlier in the storm.   

[tamarack]

Balsam fir is relatively short-lived, subject to internal defect, shallow rooted, and with dense evergreen foliage.  What's not for the wind to like?

I agree that foliage was key - by late October on LI I'd guess leaf drop had been considerable on non-oak species, so not only did they have more sail area still rigged but lacked protection from their neighbors.  In addition, oak crowns tend to be wider than those of the other species noted, and that would be particularly true on the sand-rich soils on much of the island.  That wide-branching growth habit may be why oaks in NNJ took some of the worst damage in the NW gales back on 12/31/62 - seeing bare-limbed large white oaks, usually deeper rooted than reds, being tipped out of semi-frozen soil (my temps for that day were 5/-8) was surprising.

[LongBeachSurfFreak]

2 hours ago, tamarack said:

Balsam fir is relatively short-lived, subject to internal defect, shallow rooted, and with dense evergreen foliage.  What's not for the wind to like?

I agree that foliage was key - by late October on LI I'd guess leaf drop had been considerable on non-oak species, so not only did they have more sail area still rigged but lacked protection from their neighbors.  In addition, oak crowns tend to be wider than those of the other species noted, and that would be particularly true on the sand-rich soils on much of the island.  That wide-branching growth habit may be why oaks in NNJ took some of the worst damage in the NW gales back on 12/31/62 - seeing bare-limbed large white oaks, usually deeper rooted than reds, being tipped out of semi-frozen soil (my temps for that day were 5/-8) was surprising.

What were the winds like during that event. During sandy we had about 6 hours of gusts to around 60 out of the east followed by about 2 hours with gusts to 80 out of the south east.

[Tom12309]

Interesting point.  During Irene the winds were about what we get from a big thunderstorm but from the east where a tstorm is generally NW or W around here.  In my back yard the poplars that just waved around in a summer storm fell right over if they had nothing sheltering them.

[tamarack]

13 hours ago, LongBeachSurfFreak said:

What were the winds like during that event. During sandy we had about 6 hours of gusts to around 60 out of the east followed by about 2 hours with gusts to 80 out of the south east.

NYC recorded sustained wind 43 mph, their top for Dec, but i can only estimate what we had.  However, gusts were sufficient to shatter $10k worth of windows in a nearly finished new school a couple towns away, tipped many trees, managed to create 6-ft drifts from the 2" of (originally wet) snow that fell late on 12/29.  One could track gusts by the clouds of snow flying thru the woods.  My guess is that gusts topped 60, may have reached 70.  Only the Apps gale of Nov 1950 can challenge for the strongest winds of my experience, with Hazel and Doria (NNJ) and Bob (Maine) clearly a step lower.  The wind began howling late on 12/29 after the snow ended, increased on the 30th and still more the next day, and only began to calm a bit during the overnight 31st-1st.

The 1962 winds were backside NW from the blizzard that ate BGR - 30-45" in the lower/middle Penobscot valley, temps cycling back and forth between subzero and near freezing, drifts to 16'.  A 20-year retrospect in the Bangor Daily News (which was unable to publish on 12/31, for the only time in their nearly 200 year history) included a tale of snowplows out near the airport.  A regular (for Maine) plow truck got stuck, so a 6-wheel-drive grader was sent.  When it got stuck, a large bulldozer followed, and also got stuck, at which point the operators probably retreated to Pilot's Grill for warmth inside and out.
The NFL championship, Giants-Packers, was played on 12/30 at Yankee Stadium.  Temps were mid teens (compared to NYC's 13/4 on the 31st), but according to those who sat thru both, the wind and cold combo was comparable - though 25-30° less cold - to that at the famed Ice Bowl in GB 5 years later.

[weatherwiz]

Grauple/small hail showers Monday? 

[weatherwiz]

NAM interesting across south coast as well for Saturday night. I know that's been discussed for a few days. 

[Damage In Tolland]

Nah