UKC

Dear All, it seems that the turf-temperature gauges on Great End and Helvellyn have not once registered any frozen turf all winter so far, despite extended periods of sub-zero air temperatures. This is also despite quite variable oscillating snow cover conditions - from no cover to thick cover.

I find this quite perplexing, as at 900 feet where I live, I have periodically had concrete-hard frozen grass and soil, and up to four inches of ice on my water butt. In other words - a well-frozen garden. On several occasions, and with variable snow cover.

Is there a conspiracy theory to be had here? What are the gauges actually reading? What would they read in my garden? My eyes do not deceive me.

DC

In reply to Dave Cumberland:

I agree. There's something fishy going on here and its not the cod fillet in my pocket.

In reply to Dave Cumberland:

Perhaps it’s colder in your Garden?

Interesting comparison between the Lakes data and that from Idwal, which has seen turf temps hit zero this winter.

I wondered if freezing in turf might be quite a complex process, and it looks like it is:
http://scholars.wlu.ca/cgi/viewcontent.cgi?article=1018&context=geog_fa...
Is rather jargon heavy for my understanding, but if you zoom into the first bit of the data in figure 4 you can see that there is a plateau close to zero degrees for a few days before temperature falls further - maybe due to warm water migrating towards the freezing line from the saturated level below? Mayhap one of the upland ecology types oh here could comment further....

In reply to Dave Cumberland:

I think the sensors are too deep. The shallowest is 5cm. When I’ve made turf placements I’d trust, the pick is definitely not 5cm deep. When I’ve come across iron hard turf which gives really reassuring placements, I reckon the picks were only in a few mm. When you walk on frozen ground, I very much doubt it is frozen at 5cm.

In reply to Dave Cumberland:

I guess we will eventually understand what 2 degrees at 5 cm on Great End means in terms of climbing conditions or potential climbing conditions

What the sensor patently doesn't do is give a simple answer to the conditions question

Another useful aid to finding the Ephemeral but not the last word

In reply to Dave Cumberland:

Is it possible for unfrozen well snow covered turf to subsequently freeze? A few years ago there was a reindeer famine in Siberia because it rained on the ground, froze and then snow fell on top of this. The reindeer then could not eat the frozen grass. Usually, presumably, the turf in very cold places remains unfrozen such that animals like bison and reindeer can uncover and consume it as the snow acts as an insulator.

In reply to Dave Cumberland:

I've done two trips to the Lakes this winter, one the weekend before Xmas and one the thursday after. Both times we found exactly this, down in Glenridding and Patterdale the ground was frozen rock solid and as you walked up it started softening, mainly where the snow was. Each time I thought the cliffs weren't going to be frozen but on both Hutaple and Viking Buttress exposed turf was well frozen although sometimes on the big ledges it would be softer further back onto the ledge, again where there was snow lying. The sensors both times said positive for turf at 5cms.

I'm just back from Cwm Cneifion today and the 850 mtrs sensor there still says above freezing, but the turf was absolutely bomber on the route we did.

In reply to Dave Cumberland:

Just last week at the north end of Lock Lomond we started the hikes on frozen ground and upon hitting the routes at around 600 - 800m found the ground to be much softer. Snow insulation was the only explaination we could come up with.

In reply to Dave Cumberland:

I think something important to keep an eye on is how far apart the lines are, as opposed to just the absolute temperature(with the obvious caveat that it needs to be approaching 0 degrees anyway).

If the lines are close, E.g. right now @ 7.40 the sensors say 0.8, 0.95 and 1.05 degrees with an air temp of -5.75, it means that the depth of penetration of the 'cold front' in the ground has reached a sufficient depth for freezing to occur at a range of depths and position specific locations, and as many are now reporting are finding frozen turf in place, this seems sensible.

Which for the sake of preserving the turf is good because it means that even if you are only placing picks in a few cm's the turf your pick is in, is actually attached to the turf/soil beneath it, which will mean it won't rip out, i.e. not just a crust. It's no use having the top few cm's frozen solid but below that it's several degrees warmer and saturated. I agree that in the valley, just because the grass is crusty and the ground hard, it doesn't mean that it has penetrated to any substantial depth.

I think as a guide, it is helpful, and I agree that 30cm is probably too deep, but not completely useless. Nature is a complex beast and a whole loads of different reasons will effect results e.g. slope aspect, soil type, fluid saturation level, local weather, insulation by snow, etc etc. if you also look at the longer time scales you can see the delay between air temperature and ground temperature quite nicely, which again shows that it is not quite as simple as we'd like.

I think if things are approaching 1 degree then it's looking good, and combined with some decent weather, there is no reason for things not to shape up nicely!

In reply to Dave Cumberland:

As others have said, probably a complicated picture- I guess temperature inversion could play a part- I remember being on Craig meagaidh a few years back, well below freezing in Coire ardair and t shirt weather on the summit...! Higher crags likely to be in thaw in similar conditions whatever the valley picture is

In reply to no_more_scotch_eggs:

In cold windless conditions the coldest air, because it is denser, drains down into the valleys so it is commonly coldest there overnight (temperature inversion). Thus it is often warmer higher up though wind chill may disguise the fact. If the wind then gets up during the day the turbulence mixes the air from different levels and the inversion weakens or disappears altogether.

In reply to TobyA:

In winters of late this seems to be more typical of Lake District conditions - very icy paths below and long periods of poor consolidation much higher up.

In reply to Dave Cumberland:

Dave

A friend of mine went out in the cold snap before xmas and mentioned he found the turf thermometers were reading above zero at 5cm yet when he went out he found all terrain frozen. This weekend the turf temps read similar to the cold snap before xmas but when we got to red tarn all turf was still soft even where exposed. the temps gauge on the thermometers hasn't really fluctuated at all only maybe 2 degrees when the air temp has been changing quite rapidly

Our thought was could it be the placement of the thermometers. Are they placed in sheltered areas of the crag where they are not exposed to the elements as much as its taking longer for that area to freeze or could it be the fact turf temps at these depths have always been around these temps at the time of year and its only ever been the top few cm's that ever freeze solid but we never knew this cause technology wasn't around to tell us as its only came available now. Whatever the reason they don't seen to be giving accurate readings of conditions. Probs still best to have a trip up assess the conditions and just go for a walk if they are not in. Which is what we ended up doing sat

Back to your garden, could it be the fact we are having lots of temperature inversions overnight or maybe the flat areas lower down are exposed more directly to the clear skies which is causing them to freeze solid or the fact the mountains have been insulated by a layer of snow all winter and its not allowing things to freeze solid. I'm flummoxed

In reply to David Cowley:


Agree - good points - rub noses with it is best method! I trust my own judgement better than the gauges. I live on a hill above the fog and the frost hollows, but have very thin soil that freezes quickly. I am still flummoxed like you, but I am just about to go out and test the conditions again .. .. .. .

ZIP WIRE?
THIRLMERE - NO WAY!
HONISTER - YES!

DON'T LET THE BAR STEWARDS GIVE ONE TO HONISTER THEN USE THAT AS AN EXCUSE TO GIVE ONE TO THIRLMERE.

THIRLMERE IS ENTIRELY INAPPROPRIATE, I QUESTION THE PEOPLE WHO WISH TO DO THIS. THEIR ATTITUDE IS UNACCEPTABLE IN THIS AREA.

Sorry, couldn't help myself .. .. ..
DC

In reply to Dave Cumberland:

Helvellyn ridge today frozen from car park to top.

I have thought about this some more. Regardless of absolute temperatures, conditions and gauge readings, the key influence on whether the area is "in nick" must be the amount of freeze-thaw activity. Some vegetation responds well to limited freeze-thaw and freezes up, other types never freeze and ice up unless there are many oscillating cycles of freeze-thaw with significant diurnal/weekly ranges.

It has been a problem in many winters.
DC

In reply to sheelba:


I think the problem with that theory is that the reindeers eat the grass which is actually on top of the turf rather than within it.
Whilst snow can insulate turf to some degree, clearly turf is sometimes found to be frozen underneath snow. The grass between the two would normally be edible (to reindeers!) despite this because the chemicals in it stop it from freezing. In the instance you refer to, the grass was presumably inedible because it was encased in frozen water rather than actually frozen itself.

In reply to Dave Cumberland:
Hi,

Rest assured there is no conspiracy theory I placed the sensors in N.Wales.

The probes are pushed into ground on mixed terrain. Not on a climbing route or high on a crag, but on reasonably accessible ledges, at the stated altitude near to climbing crags. The probes are within a few inches of each other, and certainly not sheltered.

They are stainless steel probes pushed in the ground on stakes to mark the depth.

Although 30cm is too deep for an ice tool, it shows the long term effects of prolonged cold spells etc, and the much slower rate of change as the air temp fluctuates, which serves as a

Often in winter conditions in North Wales, the ground probes have been insulated under snow; in those cicumstances they never get below 1degC.

It's possible that in other times with no insulation from snow cover, the surface may well be frozen but the frost has not penetrated below to where wind-chill will have a diminished effect.

Out of interest, next time your garden is bullet hard, go at it with your ice axe and have a look how deep it is frozen.

What's missing is the temperature gradient for the surface vegetation and the first couple of inches of earth.

Placing them closer to the surface would be tricky because of the persistent issue of rodents, sheep, goats, hungry climbers nibbling at the gear and disloging the wires, but worth considering.

In reply to robshep:

Having noticed Great End was reading +5 degrees this am I didn't bother to check for ice on my wife's car windscreen (langdale), does BMC legal team cover divorce.

In reply to robshep:

Are there any pictures of the location ?

Hi, can you tell me what sort of probes are used, are they RTD or Thermocouple or are they a specialist soil thermocouple ?

Also you say they are inserted on a stake for depth, are they touching the stake or just next to it for depth guidance ?

In reply to John Kelly:

Yikes. Watch out for temperature inversions

In reply to Dave Cumberland:
Just goes to show that up the hill isn't necessarily the coldest place. E.g. yesterday morning I drove to the Lecht from Dundee. At my front door at 7am (half a mile from the sea, 150ft ASL) it was minus 4. Driving up Glen Shee (8 am, 40 miles from the sea, 1200ft ASL) it was minus 9. In Braemar village (0830, 60, 1300) it was minus 4. At the Lecht (0920, 2090, 40) it was minus 3. Today MWIS says it will be minus 1 at 1300 ft and PLUS SEVEN at 3500!

In reply to Sophie G.:

-1.5 Swirls car park thirlmere helvellyn (10.30am)
+ 2 summit Helvellyn (11.30am)

In reply to Dave Cumberland:
I guess there's still nothing quite like having a look!

So with this in mind, has anyone been out to Great end recently to visually assess conditions? Is there much snow in the gullies? has anything resembling climbable ice formed?

In reply to robshep:

Are the probes mounted on stakes that would not conduct heat?

If not and if they are not insulated from the stake then the risk of rogue readings is high.