the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 29 Jun 2026
Rapid mass loss and climate-driven dynamics of the Juvfonne ice patch, Norway (2010–2025)
Abstract. Juvfonne is a small ice patch (~0.1 km2) in Jotunheimen, southern Norway, and contains the oldest ice dated in Norway so far. More than 600 artefacts have been detected along the margin. Since 2010 annual investigations of mass balance with point measurements of snow accumulation and ablation have been carried out together with surface elevation and ice patch extent measurements. The outline mapping conducted between 2010 and 2025 demonstrates that the extent of Juvfonne undergoes continuous changes along the entire margin, varying from year to year. The decrease in area from 2010 to 2024 is 46 % from 0.149 km2 to 0.081 km2. Ice thickness measurements conducted in September 2025 reveal a current maximum thickness of less than 9 meters and an interpolated mean thickness of < 3 meters. Repeat surface elevation surveys from lidar and UAV surveys reveal that Juvfonne has lost 73 % of its volume between 2011 and 2025 and thinned on average 4 m (0.30 m a-1), the value is sensitive to the outlines used. We compare the mass changes of Juvfonne with neighbouring glaciers in the Galdhøpiggen massif for the period 2011–2020 using repeated lidar surveys revealing that Juvfonne has had a smaller surface thinning than neighbouring glaciers over this period. Interpretation of data from two nearby automatic weather stations show that deposition of windblown snow on Juvfonne causes more snow accumulation than in the surroundings. The snow accumulation is dependent on wind direction and speed. Major snowfall events are associated with storms or synoptic cold fronts with westerly winds and short-term storm events can contribute greatly to the total accumulation. Ablation is related to cumulative positive degree days, but also to winter balance. Results from a Summer Melt Potential Index for the period 2010–2025 reveal a significant intensification of compounding melt events driven by the synergy of temperature, wind, and atmospheric moisture. Juvfonne prevails due to drifting snow and is controlled by topography and can fill up after years with surface lowering. However, the reduction in area and volume over the period 2010–2025 reveals that Juvfonne is vulnerable to the current warming and its current ice may completely vanish with a few warm summers.
- Preprint
(2690 KB) - Metadata XML
-
Supplement
(2588 KB) - BibTeX
- EndNote
Status: final response (author comments only)
-
RC1: 'Comment on egusphere-2026-3152', Anonymous Referee #1, 16 Jul 2026
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2026/egusphere-2026-3152/egusphere-2026-3152-RC1-supplement.pdfCitation: https://doi.org/
10.5194/egusphere-2026-3152-RC1 -
RC2: 'Comment on egusphere-2026-3152', Anonymous Referee #2, 03 Aug 2026
Review of the manuscript:
Rapid mass loss and climate-driven dynamics of the Juvfonne ice patch, Norway (2010–2025)
The Cryosphere Discussions
Authors: L.M. Andreassen and 8 others
------------------------------------------------------------------------------------------------------
General
This manuscript informs the reader about the ongoing decline in the areal extent and volume of the Juvfonne ice patch in the mountain massif Jotunheimen, Southern Norway. The authors have carefully mapped the outlines of this (currently) ~0.1 km2 ice patch from year to year, using differential GNSS, drone photography and aerial imagery. Changes in surface elevation have been monitored using lidar surveys and UAV surveys and ice thickness variations have been determined using data from GPR surveys. Moreover, the authors report on an extensive mass balance program on Juvfonne, carried out in 2010-2025. The climatology of the Juvfonna area has been assessed from weather station data, allowing estimates of the importance of snowdrift for the winter balance as well as estimates of key factors and processes governing snow and ice melt on Juvfonne.
All in all, the manuscript describes an impressive suite of observations on this vanishing ice patch and the Juvfonne results are presented in the general context of glacier changes in the Jotunheimen massif. The results are informative and mostly well worked out, with the exception of small mistakes in simple calculations presented in the text. In addition, more detailed information concerning the mass-balance measurements should be given (or referred to, if such results from Juvfonne have been published elsewhere). See comments on this below. The authors also need to address several points concerning the English language of the paper.
Given that these suggestions for improvements are taken into account, the paper should be published in The Cryosphere. The disappearance of Juvfonne and several other small glaciers in Norway is not only interesting in the context of global warming impacts on mountain glaciers, but also has important implications for archaeological studies of artefacts appearing at retreating glacier margins, often dating from pre-historic times.
Specific comments
L27
show => shows
L33-34
“Juvfonne prevails due to drifting snow and is controlled by topography and can fill up after years with surface lowering.”
This sentence needs polishing, explain how it is "controlled by topography" and what is meant by stating that Juvfonne can "fill up".
L35
with a few warm summers => within a few warm summers (or: during a few warm summers)
L37
Glaciers come in a wide range... => Glaciers exist within a wide range...
L41
and have a self-regulating mechanism allowing them to survive => where a self-regulation mechanism allows them to survive
L44
They normally have no or very limited movement => They normally display no or very limited movement
L46
with numerous signs from hunting and travelling => indicating past signs of hunting and travelling
L49
or the Ötzi man => or the iceman Ötzi
L52
...Norway's average temperature will rise most in winter...=> ...the temperature increase in Norway will be greatest in winter...
L69
To discuss Juvfonne´s behaviour within regional trends... => To discuss the changes Juvfonne has been undergoing in the context of regional trends...
L75-77
...at the Galdhøpiggen summer ski centre on the glacier Vesljuvbrean with the Juvvasshøe and Juvflye meteorological stations (Fig. 1a)...
Suggest change to:
...at the Galdhøpiggen summer ski centre on the glacier Vesljuvbrean. The automatic weather stations at Juvvasshøe and Juvflye are both located <1 km from Juvfonna (Fig. 1a).
L78
an area of 0.086 km2 and altitudinal range from 1852 to 1985 m a.s.l.=> an area of 0.086 km2 with an altitudinal range between 1852 and 1985 m a.s.l.
L79-80
...at its little ice age (LIA) maximum and had a maximum thickness of 17-19 m in 2009...
=>
...at its Little Ice Age (LIA) maximum and a maximum thickness of 17-19 m in 2009...
L89
and then a second one in 2012 was excavated => and then a second one was excavated in 2012
L113-114
in spring 2010 and comprises winter balance measurements in 25-71 points,
=>
in spring 2010, comprising winter balance measurements at 25-71 points,
L115
a glacier-wide mass balance => the glacier-wide mass balance
L116
Winter accumulation and balance measurements => Winter accumulation and winter balance measurements
L117
"Snow depth is measured by probing to the previous summer surface."
How accurately can the observers determine if they are probing the previous summer surface? Do they not sometimes encounter ice layers above the summer surface, formed during warm autumn spells? Please clarify.
L119
“Snow density is determined from a pit near the stake (Fig. 1a)...”
The authors are asked to take the following points into consideration and/or give references to publications where these issues have been addressed:
What is the vertical resolution of the density measurements? Is the density measured all the way down to the previous summer surface at S2 each year? What are the typical values of mean density of the annual layer? How is it justified to use density values from a single point to calculate SWE at all points on Juvfonne? What is the typical depth of the winter layer at stake 2?
What kind of ablation stakes are placed in the glacier? Is it ensured that these do not melt into the ice during summer? The Getis-Ord Gi* method should be described for the general reader, as well as the term: False discovery rate corrections.
L151
with the 2016 survey suffering from some doming and have lower accuracy.
=>
with the 2016 survey suffering from some doming and believed to have lower accuracy.
L155
except for Kjelen and Juvfonne that were digitised orthophotos acquired on 26 August 2019....
=>
except for Kjelen and Juvfonne, for which digitised orthophotos acquired on 26 August 2019 were used...
L178
To assess uncertainty... => To assess uncertainty in ice thickness measurements...
L188
Juvvasshøe (1894 m a.s.l.) is a full meteorological station...
=> (perhaps more appropriate to write):
Juvvasshøe (1894 m a.s.l.) is a meteorological station situated within the elevation range of Juvfonne and complete with instruments measuring air temperature, humidity, air pressure, wind speed and direction, and incoming and outgoing shortwave and longwave radiation...
L190
exposed in all directions => exposed from all directions (perhaps better)
L232
Maybe state in the beginning of this paragraph that 2009-2010 was the first glaciological year covered by mass balance measurements (instead of mentioning this in line 235).
L241-242 (caption, Fig. 3)
"Point mass balance at stake 2 at Juvfonne 2010-2025 and the mean, given as winter balance (bw), summer balance (bs) and annual balance (ba)."
No mean value seems to be indicated in the figure! Please clarify.
L244
The title of this section and much of the discussion in the paragraph on P10 seems to indicate fluctuations in the ice patch itself, whereas it seems clear from the text and Figs. 4 and 5 that it is remaining winter snow at the margins that is responsible for increased size of the "ice patch" in, say, the years 2016 and 2017. The text should convey more clearly the information that the ice mass itself is not expanding in those years.
L272
reveals => reveal
L280-281
Two sentences that say the same thing! One of them should be removed.
L283
based on the combined 2011 and 2025 extent => based on the difference between the DEMs from these two years
L290 - caption for Fig. 6
Maybe state that the man-made tunnel is located on the eastern side of the ice patch and is indicated with a (skewed) rectangle.
L295
...maximum thickness of 8.3 m located in... => maximum thickness of 8.3 m at a location in...
L301-302
"Based on a current (2025) volume of 20 m3 and an estimated volume of 73 m3 in 2011, Juvfonne has lost approximately 73% of its volume in this period."
The volume figures are really strange and the authors probably meant to write 2*105 m3 and 7.3*105 m3. This must be corrected, and the area and thickness figures used in each case should be given as well.
L305 - caption for Fig. 7
It is hard to locate a "star pattern in grey" on the figures.
L311
The maximum snow depth was measured in 2020 with 5.78 m.
=>
The maximum snow depth value was 5.78 m, measured in 2020 at a location...[state the location, f.ex. relative to stake 2.]
L311-312
"The snow depths minimum and maximum are similar to the bw measured at stake 2."
This is a strange sentence. The winter balance (bw) is calculated from the snow depth and the (mean) density at the same location. The authors probably mean to say that the min and max values of snow depth are comparable to those obtained at stake 2, or what? Please clarify!
L318
We did not include the two last years of record, 2024 and 2025, where snow was redistributed
=>
We did not include the two last years of record, 2024 and 2025, in which snow was redistributed
L321-322
Explain the results presented in Figure 8 and the relationship to the data presented in Figure S3. Is a "Hot Spot" simply a point where high snow depth is obtained and "Cold Spot" a location with low snow depth?
L336-337
"Before 7 February the air mass at Juvfonne was warm and humid with a high sea level air pressure."
This is a bit of an overstatement, unless "before" refers only to the brief warm spell on 6 February.
L340
There is a short period of one day with cold and humid conditions
=>
There is a short period of approximately 24 hours with cold and humid conditions
L344
Figure 10 caption - state that the data are from the Juvvasshøe weather station.
L354
there is a clear connection between wind speed and direction to snow accumulation.
=>
wind speed and direction correlate well with the amount of snow accumulation.
L359-360
"Most likely, erosion due to blowing snow is the key reason why the overall snowfall values are low."
This presumably refers to the snowfall values recorded at the station Juvvasshøe - the authors surely do not want to imply low values of snowfall at Juvfonne. Please amend the sentence accordingly.
L386-387
"By this time, Juvfonne typically reaches its annual minimum extent (Fig. 5), and the surrounding terrain has the least snow cover."
This sentence is not very precise, it makes it sound like the size of the patch of glacial ice varies seasonally. But normally that is not the case for an ice mass that has been steadily declining in size. - But it is true that the combined extent of ice and surviving snow cover is normally at a minimum in September.
L393
The annual variations in air temperature is illustrated... => The annual variations in air temperature are illustrated...
L398-399
"The comparison of two decades (2001– 2010 vs. 2011– 2020) reveals an approximate 1.5% increase in CPDD values, predominantly in late spring and early autumn."
Does this mean that CPDD values are 1.5% higher during 2011–2020, as compared to 2001–2010 ?
L399-400
"The correlation (coefficient of determination) with point mass balance bs and ba at stake 2 are -0.56 (0.32) and -0.41 (0.17), respectively."
Unclear formulation, state clearly that the first of the two figures is r and the one in parentheses r2.
L409
the exhibits a consistent positive trend => the SMPI exhibits a consistent positive trend
L432
we assessed the repeat lidar surveys => we investigated the repeat lidar surveys
L493
"Storbreen reduced from 0.0154 km2 to 0.0985 km2 (82%) and Lendbreen from 0.429 to 0.175 km2 (145%)."
Careful here. The figures given for Storbreen indicate an increase in size by 540% ! Thus the first figure should probably be 0.154 km2 and the decrease in that case amounts to 36% (not 82%).
The decrease of Lendbreen is ((0.429-0.175)/0.429)*100 = 59% (not 145%) - it is more appropriate to calculate area change relative to the original size than to the final size.
L509 - caption for table 1
Galhøpiggen => Galdhøpiggen
Check figures in the table - the dA figure for Kjelen (31.8%) is wrong, should be 33%.
L522-523
"... but we cannot determine any trend over Juvfonne over the observation period."
Trend in what? Summer snowfall occurrences (cf. L521) ? Please specify what is meant here.
L552-553
According to this definition it is not required to have present flow to be a glacier.
=>
According to this definition flow at present time is not a necessary condition for an ice mass to be classified as a glacier.
L570
during all the Holocene => during the entire Holocene period
L571
and serving as a key stabilizing factor. => serving as a key stabilizing factor.
L573
"particularly when accounting for three-dimensional effects."
What is meant here by "three-dimensional effects" ?
L602
with an estimated reduction of 73% of the ice patch between 2011 and 2025.
=>
with an estimated reduction of 73% of the ice patch volume between 2011 and 2025.
L612
snow removal. (cf. Dyrrdal et al., 2025). => snow removal (cf. Dyrrdal et al., 2025).
L662
will be submitted to WGMS. => will be submitted to the World Glacier Monitoring Service (WGMS).
Citation: https://doi.org/10.5194/egusphere-2026-3152-RC2
Viewed
| HTML | XML | Total | Supplement | BibTeX | EndNote | |
|---|---|---|---|---|---|---|
| 76 | 53 | 11 | 140 | 21 | 8 | 8 |
- HTML: 76
- PDF: 53
- XML: 11
- Total: 140
- Supplement: 21
- BibTeX: 8
- EndNote: 8
Viewed (geographical distribution)
| Country | # | Views | % |
|---|
| Total: | 0 |
| HTML: | 0 |
| PDF: | 0 |
| XML: | 0 |
- 1
