Hiking accidents and strong northerly winds over Mediterranean Pyrenees

Transcription

1 Hiking accidents and strong northerly winds over Mediterranean Pyrenees Ramón Pascual and Alfons Callado Meteorological Center. INM. Barcelona, Catalonia, Spain El Escorial, October, 2007

2 11 1 Geographical Features (1) Pallars-Aran Massif (3000 m a.s.l) 110 km 50 km ,4 Catalonian Pyrenees Eastern Pyrenees (2900 m a.s.l) Map: INM 70 km Coastal Ranges 2 Montseny Massif (1700 m a.s.l) Mediterranean Sea Barcelona Map: INM 2

3 Cases (1) In some cases, there is uncertainty in exact date, altitude and location. Sources: Newspapers, village councils, people s memory, etc. 0) XIX century. Noucreus (2800 m a.s.l.). 9 hikers died. 1) 17 February Tosa d Alp ( m). 1 skier died. 2) 6 March Matagalls (1400 m). 2 skiers died. 3) 27/30 December Freser Gorge ( m). 3 hikers died. 4) 8 March Freser Gorge ( m). 1 hiker died. 5) 26 November Costabona (2200 m). 3 hikers died. 6) 31 December Torreneules ( m). 3 hikers died. 7) 4 November Puigmal (2900 m). 1 hiker died. (SW flow) 8) 23 December Tirapits (2700 m). 2 hikers died. 9) 16/17 April Canigó (France) ( m). 1 hiker died. 10) 30 December Balandrau (2300 m). 9 hikers and skiers died. 11) 15 February Montardo ( m). 1 skier died. 3

4 Cases (2) Geographical distribution Cases 0, 3, 4, 5, 6, 7, 8, 9, and 10: Nuria Mountains (Mediterranean Pyrenees). (9 events). Case 1: Moixeró Range (Mediterranean Pyrenees). Case 11: Aran Valley.. Central Pyrenees. Case 2: Montseny massif.. Coastal Ranges. Monthly and seasonal distribution November: 2 cases (5 and 7) December: 4 cases (3, 6, 8 and 10) January: 0 cases February: 2 cases (1 and 11) March: 2 cases (2 and 4) April: 1 case (9) Autumn: 2 cases. Winter: 8 cases. Spring: 1 case. Unknown: 1 case. 4

5 Cases (3) Geographical and seasonal distribution Some determining factors: Social: High number of visitors (easy access with train): Nuria Mountains. Nearness to a very populated area (Barcelona). Period of holidays (December: Christmas). Orographical: Mountain form and vegetation: Nuria Mountains are soft and rounded but high mountains. Easy hiking. Itineraries over timberline. Alpine meadows. Meteorological: Corner effect in Mediterranean Pyrenees. Frequent winter sudden and strong northerly winds. Strong northerly and westerly winds also affects Montseny massif. 5

6 Geographical Features (2) Nuria Mountains , km km 9 6

7 Geographical Features (3) Cases 3 and 4: Freser Gorges Taken from 2100 m a.s.l. October) Path Planell (little plain) de les Eugues 2000 m Path Mountain hut Path R. Pascual 7

8 Geographical Features (4) Case 6: Torreneules Massif (Taken from 1200 m a.s.l. April) Accident Torreneules 2711 m 2500 m 2500 m Accident R. Pascual 8

9 Geographical Features (5) Case 7: Puigmal Massif (Taken from 2400 m a.s.l. Autumn) 2650 m Puigmal 2910 m Puigmal 2910 m Path Ll. Catasús 9

10 Geographical Features (6) Case 9: Canigó Massif Canigó 2784 m m Canigó 2784 m m 2400 m Pla Guillem 2200 m Taken from 2400 m a.s.l. February) R. Pascual (Taken from 2465 m a.s.l. January 07!!) R. Pascual 10

11 Probable cause of death: Accidents characteristics Hypothermia Fall in a mountain stream (drowned and/or subsequent hypothermia). Fall (contusions and/or subsequent hypothermia). Avalanche (contusions, hypothermia and/or asphyxiation). Probable cause of accident: Poor visibility conditions Strong winds Freezing temperatures Disorientation, loss, slip, fall Hypothermia, slip, fall Change in surface conditions Change in snow cover stability Slip, fall Avalanche 11

12 Weather conditions (1) General conditions (Estimated from evidence survivors, newspapers, NCEP and ECMWF reanalysis, scarce observations): Rapidly changing conditions. Sometimes cloudy or overcast sky. Snowfall during accident and/or previous days (fresh, loose snow). Low or very low temperatures. Strong or very strong winds. Extremely low wind chill temperatures. Poor visibility because snowfall and/or blowing snow. Whiteout conditions. Hazardous weather conditions comparable to blizzard or ground blizzard. Local name: Torb 12

13 Weather conditions (2) Estimated values of some important variables > 40 m/s Event Maximum Case Temp. (ºC) Wind Chill 300 hpa 700 hpa 850 hpa (ºC) W (m/s) W (m/s) W (m/s) 1 (Feb.) -10 / / (NE, SFC) 2 (Mar.) -5 / (NE, SFC) 3 (Dec.) -8 / / (NNW) 21 (NW) 14 (NW) 4 (Mar.) -1 /-7-9 / (WSW) 20 (W) 10 (W) 5 (Nov.) (N) 28 (N) 30 (N) 6 (Dec.) -4 /-7-16 / (NNW) 40 (NNW) 23 (NW) 7 (Nov.) (S) 23 (S) 14 (S) 8 (Dec.) (WNW) 21 (NNW) 24 (N) 44 (NE) 26 (NE) 9 (Apr.) -5 / / (NE) 27 (N) 25 (N) 10 (Dec.) -4 (-7 ) -14 (-19 ) 60 (NNW) 24 (N) 27 (N) 11 (Feb.) -8 / / (N) 20 (NNE) 15 (NE) > 20 m/s 13

14 Synoptic Features (1) Synoptic situation: Cold and dry advection. Rapid change of airmass characteristics. 1. Northerly/northeasterly (continental) advection. Cold front? 2. Northeasterly (continental) adv. Cold front? 3. Northerly adv. Cold front: NE to SW. 4. Northerly adv. Cold front: N to S. 5. Northerly adv. Cold front: NW to SE. 6. Northerly adv. Cold front: N to S. 7. Southwesterly adv. (warm/wet adv.). Cold front: W to E. 8. Northerly adv. Cold front: N to S. 9. Northerly/northeasterly (continental) adv. Cold front: NW to SE (postfrontal). 10. Northerly/northeasterly (continental) adv. Warm&cold front: N to S. 11. Northeasterly (continental) adv. Cold front: N to S. 14

15 Synoptic Features (2) 700 hpa. Z and T. Cases: 3, 4, 5 and ECMWF

16 Synoptic Features (3) 700 hpa. Z and T. Cases: 7, 8, 9 and ECMWF

17 Synoptic Features (4) 850 hpa. Z and T. Cases: 3, 4, 5 and ECMWF

18 Synoptic Features (5) 850 hpa. Z and T. Cases: 7, 8, 9 and ECMWF

19 hpa SLP Synoptic Features (6) CyclonesTracks (500 hpa, SLP). Events. Azores-Atlantic Anticyclone European trajectory Map: ECMWF Stationarity & Retrograde mov. Mediterranean trajectory Stationarity & Retrograde mov. 19

20 Synoptic Features (7) CyclonesTracks (500 hpa, SLP). Events. General characteristics: Frequent Mediterranean cyclogenesis. Special cases: 1984: Eastward moving Atlantic low. SW flow over Pyrenees. 1986: Algerian Cyclogenesis. 1992: North Sea low with fast Southward displacement. 2000: Very fast eastward moving Atlantic-Iberian low. 20

21 Mesoscale Features (1) With northerly synoptic flow over Pyrenees: Mesoscale pressure field deformation ( 850 hpa). Generation of enhanced regional wind: Tramontane. New air mass cold and dry with upstream blocking in the north side of the Pyrenees. Strong temperature/humidity gradient across the Pyrenees. Probably density current development affecting Mediterranean Pyrenees. Complex orography implies local wind acceleration in favourable places. 21

22 Mesoscale Features (2) 700 hpa. V. Cases: 3, 4, 5 and ECMWF

23 Mesoscale Features (3) 700 hpa. V. Cases: 7, 8, 9 and ECMWF

24 Mesoscale Features (4) 850 hpa. V. Cases: 3, 4, 5 and ECMWF

25 Mesoscale Features (5) 850 hpa. V. Cases: 7, 8, 9 and ECMWF

26 Vertical velocity: Mesoscale Features (6) Cases 3, 4, 5, 6, 8, 9, 10 and 11 show dry air subsiding over the Pyrenees both at 700 hpa and 850 hpa. Case 7 (SW flow) shows light upward motion. Specific humidity and vertical velocity. 26 Nov 18 UTC Maximum downward motion Dry air hpa 850 hpa ECMWF

27 Climatic context (1) Objective: To compare atmospheric conditions between the selected days with normal conditions. Time series analysis for 3 representative dates ( ): 31 December, 15 February and 31 March (Events: 4 Nov April). Time: 12 UTC. Variables analysed: Z@500 hpa, T@300, 500, 700, 850 hpa, SLP, Flow direction@ 500, SFC. Source: ERA-40 ECMWF. 27

28 Climatic context (2) Temperature time series over the Pyrenees Cold period: (73) Identifiable in 4 levels and 3 dates. Accidents: 1968, T850 Vs T700: good correlation. Pearson s corr Coldest date: 15 Feb. Warmest date: 31 March. 28

29 Climatic context (3) Climatological synoptic patterns over Pyrenees More frequent patterns ( 10 %): 1: Strong westerly flow (cyclonic) 2: Strong westerly flow (anticyclonic) 4: Northerly advection 5: Northeasterly (european) advection 30 % 10: Centred cold low 11: Centred dynamic anticyclone 29

30 Climatic context (4) Normal Flow direction over Pyrenees 500 hpa. Higher frequency (3 dates): Flow from 4 and 3 (W/NW; S/SW). SFC. Higher frequency: Flow from 4 and 1 (W/NW; N/NE) (Dec.) Flow from 1 and 4 (Feb., Mar.) 30

31 Climatic context (5) Flow direction Vs Temperature T300 (º C) T500 (º C) T700 (º C) T850 (º C) 31 DEC -49.5/ / / / 2.9 NE/NW 31 DEC MEAN FEB -50.5/ / / / 1.5 NE/NW 15 FEB MEAN MAR -49.2/ / / / 5.3 NE/NW 31 MAR MEAN Flow from 1(N/NE): Temperature < mean in all levels and dates. Flow from 4(W/NW): Depending on actual configuration (airmass). 31

32 Climatic context (6) Temperature over Pyrenees: Events vs 40 years reanalysis, Monthly means. Mean from November to April. Events temperature < mean Exception: Case SW advection. 32

33 Climatic context (7) Geographical location of low centers (SL). 30 years. 31 DEC: 27 centers North Atlantic lows. 15 FEB: 9 centers 31 DEC: 10 centers Mediterranean lows December February March 3 dates: 29 centers Map: ECMWF 33

34 Climatic context (8) L and H centers location (SL). Northerly flow. 30 years. L 3a H 16c NW L L 1b 5a H 3 L 9a H 28a H 6a L 5b 1a L L 6a 10a L 26a L 30a H 22a H 25 L 28a H H 2a H 18b H 5 H H 16b 11 H H H H 10 7a H H 1 8a H 14 L 13c 4 H 23 28b H H 21b H 30 22b H HH H H 17b 6b 20 29b 19b15c H 9 NNE L 13a H L 20 L 17a 11a 3b 15a H 24 L 5c L L 26b L 6b 1c L H L 13b 8b 24a H L 2b H 25 7b H 15b L 26c 30b L 12 L L L L 9b L 29 11b 6c 5d 3c L L L L 21 L L L 10c 14 L L 224 L 18 L 28b L L 8 24b H 12 H 21a H 19a H 18a H 16a 29a L 10b ENE NE H 27 H 28c Map: ECMWF 34

35 Climatic context (9) L and H centers location (SL). Events. H 78a NW H 1 68 H 70 H H 4 79a 68 L L 79a 78a H 05a NNE NE H 86a H 44a H 2 68 L H 78b 30 H 44b L L 79b L 86a H 05b H 86b L 3 68 L 70 L 4 68 L 00a L86b ENE H 78b L 84 (SW) 78c L L L 86c 79c L 05 00b L H 79b H 00a H 00b Map: ECMWF 35

36 Climatic context (10) L and H centers location (500 hpa). Northerly flow. 30 years. Map: ECMWF L 25a H L 2a 6 H 19b L 29a H 12 L L 26a 30a H 24 H 3 L L 9a 8a H 17b H L 1a 25 L 28a L H 2 H 22 H H 16b 5 10 H L H 14 H H L 17 L 19 18a L 20 L HL 13 7a L 18b 3a L 6 L L 5 11 L 26b L 2b L 10 H 18c H 13 H 16a H 9 H 1 H 14 H 26 H 4 H 8 L L L 25b 9b 30b L L 18 8b L 12 L 21 29b L 16 L L H 23 L 23 H 15 L 15 L4 L 28b L 7b L 8c H H 29 19a L H 1b 17a H 27 Limit of L location Pink and sky: stronger flow 36

37 Climatic context (11) Low and high centers location (500). Events. L 78a H 79 L 00b H 70 L 00a H 3 68 L 1 68 L 00c L L 79 H 84(SW) 70 L H 4 L H 05 L 2 68 L 3 68 H 86 H 1 H 1 68 H 2 H L 1 L 78a (SW) L 05 L 2 92 Map: ECMWF 37

38 Mitigation measures Knowledge of geographical features, accidents characteristics and climatological aspects suggests some mitigation measures to risk reduction: More accurate local forecasts and warnings for Mediterranean Pyrenees when northerly synoptic flow it is forecasted. Forecasts and warnings should be easy accessible at mountain resorts, tourism offices, etc. Local forecasts and warnings should contain explanations about expected environmental conditions as a whole, not only atmospheric elements. Education should be improved about mountain meteorology, specifically for mountaineers and visitors to risk areas. It should be stressed that environmental conditions can change very rapidly and rise to very dangerous levels. 38

39 Thank you for your attention Ramón Pascual CMT en Catalunya INM: 39 El Escorial, October, 2007