Storm outbreak/Widespread large hail, 11 November 2016

It had been a long time since the previous storm event, October was an incredibly slow month, with only light rain events and mostly cool weather, it had felt more like the autumn doldrums as I call them, the warm dry period that usually occurs most autumns. However finally we had a low come down, and after triggering some massive storms in NE South Australia overnight, we had some good moisture to work with the next day. Combined with a nice overhead jet, warm temperatures and a decent shear profile and very steep mid level lapse rates, we had a highly unstable atmosphere which delivered widespread large hail, and some of the worst hail damage seen in decades to some areas.

I’m not going to write too much about the other storms that occurred this day but it was a very significant outbreak. Many splitting cells occurred, with many supercells resulting. Large hail was recorded from at least half a dozen cells, with the Adelaide area, mid north, riverland and murraylands and even Kangaroo Island all experiencing this. Damaging winds were widespread, with locally destructive winds in the east extending into NSW and Vic associated with thunderstorms. Two cells in particular were the big ones in this state, one that formed off the eastern Mount Lofty Ranges, originating near Gawler, formed a huge high based supercell which died near the border. The second, forming off the northern Mount Lofty Ranges near Burra, tracked across the Riverland, eventually forming a squall line and MCS which tore through Mildura and kept on going for another hundred kilometres before weakening out and dissipating eventually. This was the cell I was on, and I tracked it from the moment the cap broke.

I had decided to stay behind this cell for a couple of reasons. Given it was out ahead of the trough at this time and after noticing the storms to my west, despite being strong storms lacked any features and just looked grey, I decided to tail it and watch it do its thing. I feel like this was a good move, the structure was far better and more interesting from this side judging by pictures I have seen. At that stage I had little idea it would become arguably the cell of the day, possibly producing a tornado west of Mildura, a long lived RFD driven hailstorm with extensive hail and local wind damage in the riverland, and probably the best lightning show in Australia so far this storm season. Secondly I had work very early the next day and simply could not commit to following the cells interstate to their best potential, would have loved to have been in Mildura for the epicness but I’m more than happy with my day.

The Cap broke in the mid arvo, and I felt the first few drops from this developing cell just to the east of Burra. I had chose this area as a target as I noticed the trough was still well west of where it was forecast, and having been burnt in the past rushing onto the triggerless flats, i decided that my best bet was the ranges of the northern Mount Lofties for something to trigger. I noticed some decent motion in this first cell, with scuddy inflow already occurring in one area. I let it drift to the east for 15 or so minute to get a full view of the updraught, and then basically followed this cell to near Waikerie, watching it gradually become more severe until the drive involved dodging downed trees and litter debris. The anvils from storms to my north completely obscured the updraught of the cell I was on until i was following nothing more than a flickering heavy rainshaft.

I abandoned it soon, and watched an epic lightshow in a featureless sky to the north, before dropping south to intercept a left mover which decided to die 20km short of me, taken out by a rogue right mover by the looks, and then had a new cell develop overhead on the ferry in Waikerie, where 5 flangs in quick succession hit, the closest couldn’t have been further than 150m. All in all a good day, we’ve been a bit spoilt in South Australia this year. Latest estimates suggest this storm has caused at least 100 million dollars in the Riverland, a huge blow for the region unfortunately.

Cap breaking and the cell of the day forming!

Cap breaking and the cell of the day forming!

The cell producing its first precip just east of Burra.

The cell producing its first precip just east of Burra.

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A strong pulse of convection on this beautiful cell began the severe phase of the storm. Looking across the broad plains west of Morgan. I wasn’t aware at first, but there is a right mover splitting off the storm in this image.

Storms start intruding from the north.

Storms start intruding from the north.

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Extroadarily bursts assosicated with the RFD send large hail and destructive winds through areas of the riverland. Kilometre after kilometre of leafy debris scattered on the road, and hail on the edges. The outflow is interacting with the inflow, and small vorticies formed underneath the updraught, with rapid motion! Very cool.

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The storm is maturing into a fully fledged supercell, and another huge downburst occurs, this one causing some serious wind damage near Waikerie. Amazing positive Cg’s leaping out the back of this.

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Shortly before I abandoned it, the cell kicks out yet another remarkable precipitation shaft, as a huge boiling storm to its south is forming. This looked like a genuine waterfall from the sky.

A better perspective of how it looked irl...bloody incredible.

A better perspective of how it looked irl…bloody incredible.

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Behind the now developing MCS, the huge backsheared anvil puts on a rather nice display of mammatus.

The anvil of a tailing storm captures some epic light at sunset near Morgan.

The anvil of a tailing storm captures some epic light at sunset near Morgan.

Some impacts of this storm.

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The typical size of the hail near Morgan. up to around an inch, the odd 3cm stone.

Hail up to around an inch in places, accumulated around shrubs.

Hail up to around an inch in places, accumulated around shrubs.

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The drive for many kilometres looked like this. Trees and branches scattered across the road. This was tame compared to some areas!

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This had blown off a shed about 100m away. The damage through this corridor was extraordinary, I wouldn’t be surprised if 140km winds or more were observed, over 50% of trees had either snapped or lost branches in places.

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The damage through this corridor was extraordinary, I wouldn’t be surprised if 140km winds or more were observed, over 50% of trees had either snapped or lost branches in places.

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The damage through this corridor was extraordinary, I wouldn’t be surprised if 140km winds or more were observed, over 50% of trees had either snapped or lost branches in places.

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Hail about 90 minutes after its occurrence.

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More roofing spread through paddocks.

Some radar images of the storms.

 

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My cell is to the east of Morgan, you can see the two right splits to its south, while it maintains a huge hail core. Down towards the southern Mount Lofties, a massive supercell is taking shape, the cell near watervale is a left moving supercell also producing golf ball sized hail, and more cells to the north out of frame are producing large hail.

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The same time as above but 256km. South of Crystal Brooke there is a supercell producing golfballs, and on the border that cell is also producing golfballs. You can see how my cell has jutted out ahead of everything in clear air and is taking full advantage.

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Shortly before I abandoned my cell, you can see strong storms to my north, a left moving v-notch to my west, and a huge supercell to the south. I was surrounded by strong storms. The v-notch died rapidly at the back with everything else as the trough rushed inland. For a brief period (no pics), it did sustain a rather impressive bell shaped wall cloud. The cells to my north put on a spectacular lightning barrage.

And finally satellite.

This taken as the majority of the cells pictured start producing severe weather.

This taken as the majority of the cells on satellite start producing severe weather.

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There were no shortage of cells to chase this day! Mines in the middle there, becoming surrounded by other cells.

As the MCS begins to form, all that separates many storms now are their overshoots!

As the MCS begins to form, all that separates many storms now are their overshoots!

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3 Responses to Storm outbreak/Widespread large hail, 11 November 2016

  1. mancunian1957 says:

    Hi Mark – we got caught just north of Rhynie in a very localised hail storm that caused extensive damage to the car. Hailstones about 5cm across, sunshine and 27C – it was bizarre. Didn’t realise the extent of the storm. Great pictures.

    • Mark Dawson says:

      I have to say, you got extraordinarily unlucky, that was a tiny LP supercell on the dryline which produced a very narrow area of large hail damage. Storms like that are rare as in SA, will probably never happen to you again!

  2. Spectacular photos and dramatic commentary – what a day! I don’t recall ever seeing hail dumps like those. It seems from experience over the past decade or so that big storms and supercells can form in the mid-north and move approx east or south-east down onto the plains without losing strength due to any rainshadow effect from the higher ground. Whereas further south, storms coming from the ranges are much more likely to lose power as they drop down onto the plains and leaving a large strip of the western mallee with colder air and rainout areas (I haven’t looked on the radar loop to see if that happened on this occasion but it has on a couple of chases I’ve been on in that area of the mallee).
    PS glad your vehicle survived unscathed again! 🙂 Sorry about your car mancunian1957 😦

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