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  #12261  
Old Posted Jan 11, 2019, 8:41 PM
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Originally Posted by MonctonRad View Post
We call them wind tunnels in the Maritimes. Downtown Halifax is pretty notorious for wind tunnel effects in the winter time.
NIMBYs like to argue that everything over 3 storeys will create a wind tunnel, but the wind studies tend to show modest effects.

New buildings in downtown Halifax need to have wind studies and they don't get approved if they have a significant negative impact on winds around them. Usually it's pretty easy to mitigate wind effects by adding some kind of screen or setback somewhere on a highrise. The worst building in downtown Halifax is the Maritime Centre and it is getting a new podium that will reduce wind at street level.

The most common effect is "downwash" where the wind hits a building facade and is channeled down to street level. In this scenario you'd think the wind would still only be a fraction of the wind speed that you would experience in an open area. People notice it when they're going from sheltered to unsheltered areas, but that doesn't mean that buildings are generating extra wind speed, which is kind of physically implausible.
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  #12262  
Old Posted Jan 11, 2019, 8:55 PM
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The buildings cause the wind to funnel, which increases the speed. Same effect as tsunamis. That one in Japan, for example - the buildings made the water around them speed up.

Not as much of an issue in St. John's because the downtown is sheltered and has very few straight streets. Everywhere else is always windy anyways lol
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  #12263  
Old Posted Jan 11, 2019, 9:04 PM
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Originally Posted by SignalHillHiker View Post
The buildings cause the wind to funnel, which increases the speed. Same effect as tsunamis. That one in Japan, for example - the buildings made the water around them speed up.
Sure, it's possible, but how much does it really happen? You can build the equivalent of a garden hose nozzle for wind. But that is not what most streets and buildings look like, and is not the effect that is generally seen in wind studies even before attempts to mitigate wind.

Most people who argue that there are wind tunnels say that they were walking next to a building one time and there was wind. This is not proof of a wind tunnel effect in the sense of increasing wind speed (e.g. the wind speed is recorded at 30 km/h at a weather station but buildings cause wind somewhere to hit 50 km/h), or an increase to wind chills. You'd have to show that the wind speed was greater than what it would have been in an open area.

It's kind of like the urban legend about mirror-like glass facades burning people or lighting things on fire. It's theoretically possible. But it's not the typical outcome of putting reflective glass on a building, and it wouldn't happen at all without a specific shape. The worst you'd get from a typical flat facade is reflection that is somewhat less intense than direct sunlight (the mirror isn't perfectly reflective, and when you deflect wind as in the downwash case not all of the kinetic energy will be directed down to people at street level; some will be lost to friction, eddies, etc.).

It's a bit silly because if you talk about downtown Halifax people will often bring up wind tunnels but it's much windier, predictably, out in suburban strip mall type areas that have vast open areas for parking. The reputation or urban legend causes people to believe the opposite of reality.
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  #12264  
Old Posted Jan 11, 2019, 9:08 PM
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Originally Posted by someone123 View Post
NIMBYs like to argue that everything over 3 storeys will create a wind tunnel, but the wind studies tend to show modest effects.

New buildings in downtown Halifax need to have wind studies and they don't get approved if they have a significant negative impact on winds around them. Usually it's pretty easy to mitigate wind effects by adding some kind of screen or setback somewhere on a highrise. The worst building in downtown Halifax is the Maritime Centre and it is getting a new podium that will reduce wind at street level.

The most common effect is "downwash" where the wind hits a building facade and is channeled down to street level. In this scenario you'd think the wind would still only be a fraction of the wind speed that you would experience in an open area. People notice it when they're going from sheltered to unsheltered areas, but that doesn't mean that buildings are generating extra wind speed, which is kind of physically implausible.
There are certainly plenty of locations in Ottawa-Gatineau where you have tall buildings in the middle of open spaces and where there is definitely way more wind right next to the buildings, than there is in totally unsheltered areas nearby.

The Tunney's Pasture federal office complex is a prime example.

https://www.google.com/maps/place/Tu...!4d-75.7384897

From what I know of it and the occasional times I've been there, even on winter days with light winds (in unsheltered areas - which is most of the area of the complex) it's noticeably windier as you approach the shadow of the buildings.
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  #12265  
Old Posted Jan 11, 2019, 9:19 PM
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Originally Posted by Acajack View Post
There are certainly plenty of locations in Ottawa-Gatineau where you have tall buildings in the middle of open spaces and where there is definitely way more wind right next to the buildings, than there is in totally unsheltered areas nearby.
The wind speeds tend to be lower at ground level and higher as you go up. So maybe the surface speed is 10 km/h but at 100 m it's 50 km/h, and the buildings are (imperfectly) deflecting those higher winds down to ground level.

That effect is relatively easy to mitigate by adding screens and setbacks to the building.

It's not really a tunnel or funnel type effect. My problem with the wind tunnel effect (as NIMBYs tend to talk about it at least) is that they tend to think of it as being caused partly by having buildings close together (to make a funnel-like shape or whatever the mechanism is supposed to be). But the closeness if anything is probably good for reducing wind speeds, since some buildings are effectively in the wind shadow of others. For downwash the worst scenario is going to be that Tunney's Pasture type setup where there is a highrise in the middle of a field. Suburban areas are the worst for wind.
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  #12266  
Old Posted Jan 12, 2019, 3:23 AM
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It looks like Abbotsford was the hot spot yesterday at 12.6.

Not 100% sure but it was the warmest high I could find.
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  #12267  
Old Posted Jan 12, 2019, 6:58 AM
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7 degrees in Calgary at midnight. Not gonna lie, it’s nice being out in my T-shirt at night in January
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  #12268  
Old Posted Jan 12, 2019, 8:07 AM
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Cold, and only going to get colder. Will likely remain below average for most of the rest of January. It still probably won't me overall below average for the whole month though, because of how mild a start we got.

Our high was -7.5, low of -13.8, which is the coldest of the season so far.
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  #12269  
Old Posted Jan 12, 2019, 8:18 AM
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Originally Posted by Metro-One View Post
It looks like Abbotsford was the hot spot yesterday at 12.6.

Not 100% sure but it was the warmest high I could find.
my car was reading 14 and 13.

My window is open tonight, otherwise its too warm inside. You either freeze or you sleep uncomfortably hot in this old building.
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  #12270  
Old Posted Jan 12, 2019, 12:08 PM
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It's a beautiful morning. Bedroom window open (pretending I'm in BC I guess), a little fresh air in the house. Lovely.

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  #12271  
Old Posted Jan 12, 2019, 2:00 PM
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Sun and cloud, 2 degrees at 10:30 am. Should be a nice day.
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  #12272  
Old Posted Jan 12, 2019, 7:18 PM
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Last edited by SignalHillHiker; Jan 12, 2019 at 7:28 PM.
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  #12273  
Old Posted Jan 12, 2019, 9:14 PM
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CBC Vancouver just showed some pictures from Sunset Beach. Flowers a bloomin!
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  #12274  
Old Posted Jan 13, 2019, 2:40 PM
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Sunny, some cloud, and -3. Should warm up to around freezing today.
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  #12275  
Old Posted Jan 13, 2019, 3:00 PM
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Frigid -16C with a windchill of -26 in Moncton at 11AM.

It's all good though, that winter storm is staying well to the south and is busily harrying a broad swath from NJ to VA. I hope they enjoy it!

Still no storms on the horizon for the next week in NB, but I see that pesky American storm will curve up the seaboard and smack the Avalon on Tuesday. There are special weather statements already issued. Have fun Marty & Signal!!
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  #12276  
Old Posted Jan 13, 2019, 3:06 PM
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^ Just as our snow depth is finally getting down to a more normal amount (8 cm), yay.

Looks like it may transition to rain in St. John's, so Wednesday is looking awfully disgusting.
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  #12277  
Old Posted Jan 13, 2019, 3:36 PM
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Looks like a lot more than 8cm to me. Once again miserable and cold.

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  #12278  
Old Posted Jan 13, 2019, 5:51 PM
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One thing about these Arctic highs is they bring nothing but sunshine with them. Currently -6C and sunny.
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  #12279  
Old Posted Jan 13, 2019, 6:29 PM
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Sig, your picture is of the piles of snow that the snowplow throws on the lawn. If I had to judge how much snow was on the ground based off what's near the side of the road by my house, I'd have to guess 3 feet.

The back yard away from the road however.....
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  #12280  
Old Posted Jan 13, 2019, 6:31 PM
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Originally Posted by Marty_Mcfly View Post
Sig, your picture is of the piles of snow that the snowplow throws on the lawn. If I had to judge how much snow was on the ground based off what's near the side of the road by my house, I'd have to guess 3 feet.

The back yard away from the road however.....
Indeed. If I was to guess the snow depth in the backyard of my house in Moncton, I would guess maybe about 9 inches. The piles of snow on the curb in front of my house however are about 3-4 feet tall.
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