The Annapurna Circuit: Everything a Solo Trekker Needs to Know

The Annapurna Circuit was once the greatest teahouse trek on Earth — a 230 km loop around the Annapurna massif crossing a 5,416m pass through landscapes that shift from subtropical rice paddies to Tibetan plateau. It still is, arguably, but with caveats. Roads have eaten 75% of the original trail. Jeeps enable fatal rapid ascent. And a 2023 mandatory guide rule means "solo" no longer means "alone."

This guide covers the route as it exists in 2026-2027, not as it existed in the guidebooks you read from 2010.


1. Day-by-Day Itinerary: The Standard 14-18 Day Route

The full Annapurna Circuit covers 160-230 km depending on start/end points and side trips. Most trekkers complete it in 12-18 days of walking. Here is the classic counterclockwise itinerary with current (2026) road-bypass options.

DaySegmentAltitude (m)Distance (km)Walking TimeNotes
0Kathmandu/Pokhara to Besisahar7606-7h driveBus or jeep. Many now jeep to Jagat or Chame to skip road sections
1Besisahar to Bahundanda1,310~125-6hSubtropical. Hot and humid. NATT trail available to bypass road
2Bahundanda to Tal1,700~145-6hWaterfall at Chamje. Enter Manang District at Tal
3Tal to Dharapani1,860~125-6hFollow Marsyangdi River. Option to detour via Bagarchap
4Dharapani to Chame2,670~175-6hDistrict HQ. First views of Annapurna II. Pine forest begins
5Chame to Upper Pisang3,300~145-6hApple orchards at Bratang. Choose Upper Pisang (quieter, better views) over Lower
6Upper Pisang to Manang (via Ghyaru/Ngawal)3,540~207-8hCritical bypass: Ghyaru-Ngawal high route avoids road. Stunning Annapurna views
7Manang — acclimatization day3,540variesvariesDo not skip. Hike to Ice Lake (4,620m) or Gangapurna Lake. Attend HRA altitude briefing
8Manang to Yak Kharka4,050~104-5hGradual ascent. Vegetation thins. Last proper tea houses
9Yak Kharka to Thorong Phedi4,525~83-4hOr continue to High Camp (4,850m) — shorter pass day but harder acclimatization
10Thorong La Pass (5,416m) to Muktinath3,800~189-12hTHE day. Leave 3-5 AM. Details in Section 3
11Muktinath to Kagbeni2,800~113-4hDescend into Kali Gandaki valley. Muktinath temple worth visiting
12Kagbeni to Jomsom2,720~103hWindy afternoon. Walk early. Road section begins
13Jomsom to Tatopani (or bus/jeep)1,190~407-8h or 3h by jeepMost trekkers take transport. Tatopani has hot springs
14Tatopani to Ghorepani2,860~136-7hSteep climb. Rhododendron forest in spring
15Ghorepani — Poon Hill sunrise (3,210m) — Nayapul1,070~187-8h4:30 AM start for Poon Hill. Descend to Nayapul, bus to Pokhara

Total walking days: 13-15 (plus 1-2 rest days). Total elevation gain: ~4,656m net from Besisahar to Thorong La.

Sources: Himalayan Trekkers — altitude and days guide, Discover Altitude — distance and altitude profile, Travel Lexx — day-by-day itinerary, Magical Nepal — detailed itinerary.


2. The Road Problem

This is the single biggest issue facing the Annapurna Circuit in 2026 and the reason some trekkers now skip it entirely.

How much is road?

Up to 75% of the original Annapurna Circuit route has been impacted by road construction. A maintained road now runs from Besisahar to Manang on the east side, and from Pokhara through the Kali Gandaki valley to Muktinath on the west side. Only two sections of 2-3 walking days are entirely road-free: the Thorong La crossing and the Ghorepani/Poon Hill section.

Sources: Nepal Eco Adventure — road construction impact, MountainIQ — road construction guide, Wikipedia — Annapurna Circuit.

Has it ruined the trek?

Not if you use the bypass trails. In 2024-2025, you can walk 95% of the Annapurna Circuit on natural trails using the NATT (Natural Annapurna Trekking Trails), created by Nepalese guide Prem Rai and Dutch trekker Andrees de Ruiter. These trails are waymarked blue and white (the main circuit uses red and white).

Key NATT bypasses:

A free NATT guidebook PDF is available, or pick up a paper copy in Thamel, Kathmandu.

Sources: Horizon Guides — road-free itinerary, Der Eskapist — solo on new trails, Amazon — NATT guidebook.

The honest verdict

The Annapurna Circuit is not the wilderness experience it was in 2005. On the road sections, you will walk alongside (or on) dusty jeep tracks with occasional vehicles passing. But with NATT trails, route knowledge, and a willingness to take the upper paths, the core experience — subtropical forest transitioning to alpine desert, crossing a 5,416m pass, descending into a different cultural world — remains intact and is still one of the world's great treks.


3. Thorong La Pass (5,416m) — The Crux

The day

This is the hardest day of the entire circuit and one of the highest trekking passes in the world.

DetailData
Elevation5,416m / 17,769 ft
Start pointThorong Phedi (4,525m) or High Camp (4,850m)
End pointMuktinath (3,800m)
Total walking time9-12 hours
Ascent570-890m (from High Camp or Phedi)
Descent1,616m to Muktinath
Departure time3:00-5:00 AM — non-negotiable

Why the early start matters

Strong winds develop a few hours after sunrise and intensify through the afternoon. By noon, the pass can be dangerously windy with wind chill plummeting temperatures well below what your gear can handle. Trekkers who depart at 6 AM or later face significantly worse conditions than those who leave at 4 AM.

Temperature

Expect -5C to -15C at the pass in the pre-dawn hours, with wind chill making it feel much colder. Even in peak season (October), you need a serious down jacket, wind-proof layers, insulated gloves, and a balaclava. See our gear guide for specific recommendations.

Thorong Phedi vs. High Camp

Thorong PhediHigh Camp
Altitude4,525m4,850m
ProsMore tea house options, lower sleep altitudeShorter pass day (2-3h less), higher success rate
ConsLonger pass day, 890m ascentHigher sleep = worse night, limited lodges

Most experienced trekkers recommend sleeping at High Camp to shorten the pass day, provided you are acclimatizing well.

What happens if the pass closes

Thorong La can close due to heavy snowfall, blizzards, or avalanche risk. This happens most often December-February but can occur anytime. If closed:

  1. Wait it out. Thorong Phedi has limited supplies for 1-3 days
  2. Turn back to Manang and take a jeep from Manang to Besisahar
  3. Nar Phu Valley alternative: If you planned ahead with the required restricted-area permit ($100/person), you can cross Kang La (5,320m) instead — though this is a harder, more technical pass
  4. There is no safe way to "push through" a closed pass. The 2014 disaster killed 43 people who were caught in exactly this situation

Sources: Access Nepal Tour — Thorong La complete guide, Responsible Travel — crossing guide, Backpackers Wanderlust — Phedi to High Camp, Wikipedia — Thorong La.


4. Altitude Profile and Acclimatization Schedule

Sleeping altitudes night by night

NightLocationSleeping AltitudeGain from Previous Night
1Bahundanda1,310m
2Tal1,700m+390m
3Dharapani1,860m+160m
4Chame2,670m+810m
5Upper Pisang3,300m+630m
6Manang3,540m+240m
7Manang (rest day)3,540m0 — mandatory
8Yak Kharka4,050m+510m
9Thorong Phedi/High Camp4,525-4,850m+475-800m
10Muktinath3,800m-725 to -1,050m
11Kagbeni2,800m-1,000m

The critical acclimatization stop: Manang (3,540m)

Manang is the unofficial acclimatization capital of the Annapurna Circuit. Do not skip your rest day here. This is the last safe plateau before you enter the extreme altitude zone.

What to do on rest day:
- Hike to Ice Lake (Kicho Tal, 4,620m): The single best acclimatization day hike on the circuit. 7 hours round trip, ~1,080m elevation gain. Textbook "climb high, sleep low"
- Hike to Gangapurna Lake: Shorter, easier option (1-2 hours)
- Attend the HRA (Himalayan Rescue Association) altitude briefing: Free daily talk on altitude sickness symptoms and prevention
- Do NOT just sit in your tea house. Active rest with altitude exposure is far more effective than passive rest

When to add a second rest day

Add an extra rest day at Manang if you have any AMS symptoms (headache, nausea, poor appetite, dizziness). Also consider adding a rest day at Yak Kharka (4,050m) if you're feeling the altitude.

The golden rule above 3,000m: Never increase sleeping altitude by more than 500m per day. For the full science behind this, read what altitude actually does to your body. The itinerary above mostly follows this, but the jump from Chame (2,670m) to Upper Pisang (3,300m) at +630m is aggressive — monitor yourself carefully that night.

Sources: Magical Nepal — altitude sickness guide, Nepal Hiking Team — acclimatization in Manang, Laidback Trip — Manang day trips, Travel Lexx — Ice Lake hike.


5. Tea Houses: What to Expect

Quality gradient

Tea house quality drops dramatically with altitude:

ZoneAltitudeWhat You Get
Lowland (Besisahar-Dharapani)760-1,860mMulti-story concrete buildings, private rooms, attached western bathrooms, hot water, Wi-Fi
Mid-altitude (Chame-Manang)2,670-3,540mBasic rooms, shared bathrooms, intermittent hot water, charging available ($1-3)
High altitude (Yak Kharka-Thorong Phedi)4,050-4,850mBare minimum: thin walls, shared dorms, no showers, freezing at night, limited menu
West side (Muktinath-Jomsom)2,720-3,800mBetter quality again — road access means supplies are easier

NTNC-regulated pricing

The Annapurna Conservation Area is managed by the National Trust for Nature Conservation (NTNC). Tea houses are monitored and must follow fixed pricing, standard menus, and building limits (caps on how many tea houses can operate on each route section).

Current approximate prices (2025-2026):

ItemLowlandHigh Altitude
Room per nightNPR 500-1,000 ($4-8)NPR 1,000-2,000 ($8-17)
Dal bhatNPR 500-700 ($4-6)NPR 700-1,000 ($6-10)
Noodles/pastaNPR 400-600NPR 600-900
Tea/coffeeNPR 100-200NPR 200-400
Charging devicesFreeNPR 100-300 ($1-3)
Hot showerFree or NPR 100NPR 300-500 ($3-5)
Wi-FiFree or NPR 100NPR 200-500 ($2-5)

Important: Many tea houses offer free or cheap rooms if you eat all meals there. This is the norm — asking for a room without eating there will cost significantly more.

Budget estimate: $25-35 per day for food + accommodation on the trail.

Sources: OneSeed Expeditions — tea house guide, Nepal Eco Adventure — tea house prices, Follow Alice — accommodation guide, The Himalayan Odyssey — accommodation guide.


6. Direction Debate: Counterclockwise vs. Clockwise

The overwhelming consensus: counterclockwise (east to west)

99% of trekkers walk the Annapurna Circuit counterclockwise — from Besisahar up the Marsyangdi valley, over Thorong La, and down the Kali Gandaki.

FactorCounterclockwise (standard)Clockwise
AcclimatizationGradual ascent over 7-8 days to Thorong La. Manang provides perfect rest stopWest side offers no equivalent acclimatization village. Rapid altitude gain
Thorong La approach~570m ascent from High Camp. Manageable~1,200m ascent from Muktinath side. Steep, relentless, and dangerous
Road problemRoad sections come first (east side) when you're fresh, trail sections come laterTrail sections first, road sections last — ends with a whimper
SocialYou'll meet other trekkers going the same direction. Safety in numbers for pass dayNearly alone. Very few tea houses expect clockwise trekkers
SceneryWalking "into" the mountains as landscape transforms. Dramatic reveal at Thorong LaMountains behind you. Less dramatic progression

When clockwise might make sense

Almost never for the standard circuit. The only argument is avoiding crowds, but the risks of poor acclimatization and the 1,200m brutal ascent from the west side make it a poor trade-off for all but very experienced high-altitude trekkers.

Sources: Wikipedia — Annapurna Circuit, Backpack Adventures — ultimate guide, TripAdvisor — clockwise discussion.


7. Permits and Costs

Required permits (2026)

PermitCost (Foreigners)Cost (SAARC)Where to Get
ACAP (Annapurna Conservation Area Permit)NPR 3,000 + 13% VAT (~$30)NPR 1,000NTNC offices in Kathmandu (Bhrikutimandap) or Pokhara (Lakeside), or at Besisahar gate. Also available via NTNC e-permit portal
TIMS (Trekkers' Information Management System)Not required as of 2023Checkpoints verify ACAP only

The mandatory guide rule (2026)

Since April 1, 2023, all foreign trekkers must employ a licensed, TAAN-certified guide through a registered trekking agency. As of March 2026, Nepal eased rules for restricted areas to allow solo travelers to apply for permits without a second person — but a guide is still mandatory.

Enforcement reality: The Kathmandu Post reported in February 2025 that the "solo ban fails to deter trekkers from Annapurna Circuit," and multiple 2024-2025 trip reports indicate inconsistent enforcement. However, digital permit scanners at checkpoints are being rolled out, and enforcement is tightening for 2026-2027. Plan to have a guide.

Guide cost: $25-35/day. For a 15-day trek: $375-525. Our agency guide covers how to find a reputable agency and what to pay.

Total budget

CategoryBudgetStandard
ACAP permit$30$30
Guide (15 days)$375$525
Porter (optional, 15 days)$300$375
Food + lodging on trail$375-525$450-600
Transport (Kathmandu-Besisahar + Jomsom-Pokhara)$30-40$175-200
Tips (guide + porter)$75-150$100-200
Gear rental (if needed)$50-100
Total (in-Nepal)$1,235-1,670$1,655-1,930

Use the budget calculator to plan your spend, or read the real cost of trekking Nepal for a full breakdown.

Sources: Shikha Adventure — 2026 permits update, Himalayan Adventure Treks — permit fees 2026, Kathmandu Post — solo ban enforcement, Best Heritage Tour — mandatory guide rule, Himalayan Masters — cost breakdown.


8. Getting There and Back

To the trailhead: Kathmandu/Pokhara to Besisahar

OptionDurationCostNotes
Bus: Kathmandu to Besisahar6-7 hours~$15From Gongabu (New) Bus Park. Daily departures
Private jeep: Kathmandu to Besisahar5-6 hours~$175 totalFaster, more comfortable
Flight + bus: Kathmandu to Pokhara (25 min flight) + bus to Besisahar3-4 hours total~$100-130Fastest option
Jeep: Besisahar to Chame/Dharapani3-5 hours$15-30Common shortcut. Skips road sections. Recommended

From the end: Jomsom/Muktinath to Pokhara

OptionDurationCostNotes
Flight: Jomsom to Pokhara20-25 min~$160 one-wayMorning flights only (6:15-10:00 AM). Frequently cancelled by wind/weather. Book but don't count on it
Local bus: Jomsom to Pokhara10-12 hours~$20Rough road. Dusty. Long
Shared jeep: Jomsom to Pokhara8-10 hours~$40-50/personMost common option
Private jeep: Jomsom to Pokhara8-10 hours~$280 totalWorth splitting with other trekkers

Warning about Jomsom flights: They operate only in early morning before Kali Gandaki winds pick up. Cancellations of 2-5 consecutive days are common. Do not book an international flight home for the day after your planned Jomsom flight. Build 2-3 buffer days.

Sources: Namaste Nepal Trekking — Kathmandu to Besisahar, Nepal Flight Ticket — Jomsom flights, HoneyGuide — getting to Jomsom.


9. The Jomsom-Muktinath Jeep Death Trap

This is one of the most under-reported dangers on the Annapurna Circuit, and it kills people every year.

The problem

The road from Pokhara (822m) to Muktinath (3,800m) enables motorized ascent of 3,000m in a single day. Pilgrims — particularly Indian religious tourists visiting Muktinath temple — routinely drive from Pokhara to Muktinath in one long jeep ride without any acclimatization.

The death toll

Who is at risk

Primarily non-trekkers arriving by vehicle: religious pilgrims, tourists on jeep tours, and anyone who drives directly to Muktinath or Jomsom without spending nights at intermediate altitudes. Trekkers walking the circuit counterclockwise are at far lower risk because they acclimatize over 7-10 days before reaching this altitude.

What this means for circuit trekkers

If you are walking the circuit in the standard counterclockwise direction, you arrive at Muktinath on the descent from 5,416m — you are already well-acclimatized. The risk is minimal.

The danger is if you skip ahead by jeep — for example, taking a jeep from Besisahar directly to Manang (3,540m) to save time. This replicates exactly the rapid-ascent pattern that kills the jeep pilgrims. Do not do this.

Sources: Nepal York — 18 deaths in Annapurna region, Himalayan Times — 7 deaths in Mustang, Nepal Khabar — 11 deaths.


10. Side Trips Worth Taking

Tilicho Lake (4,919m) — Highly Recommended

The world's highest large lake. A 2-3 day detour from the main circuit, branching off between Manang and Yak Kharka.

DetailData
Altitude4,919m (16,138 ft)
Days added2-3
RouteManang → Khangsar → Tilicho Base Camp → Tilicho Lake → return to main trail
DifficultyChallenging — narrow paths, exposed terrain, limited lodges
Best forExperienced trekkers who want the most spectacular high-altitude lake in the Himalayas

The approach through the Khangsar valley is demanding but the reward — a turquoise lake ringed by ice-covered peaks including Tilicho Peak, Annapurna II, and Gangapurna — is extraordinary. Not many trekkers take this detour, which is part of its appeal.

Sources: Laidback Trip — Tilicho side trip, Full Time Explorer — Tilicho itinerary.

Ice Lake / Kicho Tal (4,620m) — Essential

Not really a "side trip" — this should be your mandatory acclimatization day hike from Manang.

DetailData
Altitude4,620m (15,157 ft)
Time7 hours round trip from Manang
Elevation gain~1,080m
Trail startClearly signed from Braga village

Pushing to 4,620m and returning to sleep at 3,540m is textbook altitude training. The lake itself is stunning — frozen in winter, crystal blue in summer — with panoramic views of Tilicho Peak, Annapurna I and II, Gangapurna, Chulu East, and Pisang Peak.

Sources: Travel Lexx — Ice Lake hike, Magical Nepal — Ice Lake guide, The Outbound — Kicho Tal.

Pisang Peak (6,091m) — Expedition, Not a Day Trip

This is a proper mountaineering peak, not a trekking side trip.

DetailData
Altitude6,091m (19,984 ft)
Permit cost$125 (autumn) / $250 (spring) + $500 refundable garbage deposit
Total cost with agency$2,000-3,500
Duration added4-6 days
Skills requiredBasic crampons, ice axe, rope work

Only consider this if you have mountaineering experience and want to bag a 6,000m peak. It combines well with the circuit but is a fundamentally different undertaking.

Sources: Nepal Adventure Trail — Pisang Peak guide, Peace Nepal Treks — permit costs.


11. Annapurna Circuit vs. Annapurna Base Camp (ABC)

For trekkers with limited time, this is the core decision.

FactorAnnapurna CircuitAnnapurna Base Camp
Duration14-21 days7-12 days
Max altitude5,416m (Thorong La)4,130m (ABC)
DifficultyHard. Extended high altitude, long days, 5,000m+ passModerate. Steep but shorter
Landscape varietyEnormous. Subtropical → alpine → Tibetan plateau → Kali Gandaki valleyLimited. Forest → glacier → mountain amphitheater
Cultural varietyHindu lowlands → Tibetan Buddhist Manang → MustangGurung villages throughout
Road problemSevere on parts of the circuitLess affected — trail is foot-only above Chhomrong
AMS riskSignificant. 1,300m higher max altitudeLower but still present above 3,500m
The "wow" momentCrossing Thorong La at dawn. The sheer scale of completing a circuit around an 8,000m massifStanding in the Annapurna Sanctuary — a natural amphitheater of 7,000-8,000m peaks surrounding you
Best for3+ weeks in Nepal, wants the classic long trek, comfortable at high altitude10-14 days total, wants dramatic mountain views without extreme altitude

Honest recommendation

If you have 2 weeks or less in Nepal total: do ABC. It's a more concentrated experience, less impacted by roads, and the Sanctuary amphitheater is genuinely one of the most dramatic mountain landscapes on Earth.

If you have 3+ weeks and want the defining Nepal trek: do the Circuit with Tilicho Lake and Ice Lake side trips. Despite the roads, the full experience of circumnavigating an 8,000m peak through multiple climate zones and cultural regions is unmatched.

Sources: The Mountain Company — ABC vs Circuit, Magical Nepal — comparison, Earth's Edge — comparison.


12. Weather and Best Months

Season breakdown

SeasonMonthsConditionsVerdict
Autumn (post-monsoon)Oct-NovClear skies, stable weather, cool nights, best visibilityPeak season. Best overall conditions
Spring (pre-monsoon)Mar-MayWarming, rhododendrons blooming, some haze, snow melt improves trailsSecond best. Fewer crowds than autumn
WinterDec-FebCold, Thorong La often blocked with snow, many tea houses closedNot recommended unless experienced
MonsoonJun-SepHeavy rain on east side. Kali Gandaki (west) is in rain shadow and passablePossible but challenging. Leeches below 3,000m

October: The best and most dangerous month

October offers the most stable weather and clearest mountain views, making it the most popular month. But October also carries a specific risk: late-monsoon cyclones.

The 2014 disaster

On October 14, 2014, Cyclone Hudhud — a tropical cyclone in the Bay of Bengal — merged with an upper atmospheric trough and drove a catastrophic snowstorm into the Annapurna and Dhaulagiri ranges. 1.8 meters of snow fell in 12 hours. Over 200 trekkers were on or near Thorong La.

43 people died, including 21 trekkers of various nationalities, plus guides, porters, and yak herders. 407 people were rescued, including 226 foreigners. Bodies were found frozen on the trail. It was Nepal's worst trekking disaster.

What changed:
- Weather monitoring and early warning systems improved (though still imperfect)
- More tea houses at high altitude serve as emergency shelters
- ACAP checkpoints now track trekker locations more closely
- But the fundamental risk remains: October is cyclone season in the Indian Ocean, and storms can reach the Himalayas

Recommendation: If trekking in October, check weather forecasts obsessively (especially Bay of Bengal cyclone tracking). If a storm is predicted, descend immediately. Do not attempt Thorong La in deteriorating weather.

Sources: Wikipedia — 2014 Nepal snowstorm disaster, National Geographic — deadly blizzard, Backpacker — inside Nepal's deadly blizzard, NASA Earth Observatory — blizzard in Nepal.


13. Crowds

The numbers

The Annapurna region set a record in 2024: 244,045 foreign trekkers, a 27% increase over 2023 and exceeding the pre-COVID peak by a significant margin. This number covers all Annapurna treks (Circuit, ABC, Poon Hill, Mardi Himal), not just the circuit.

When it's worst

October and November account for nearly half the annual total. In 2024, 8,853 trekkers entered in October and 6,902 in November. The second peak is March-May (spring season).

Where it's worst

LocationCrowd LevelWhy
Poon HillExtremely crowdedShort trek from Pokhara. Day-trippers and Poon Hill-only trekkers
ManangCrowded in peak seasonEveryone stops to acclimatize. Limited tea houses
Thorong La pass dayModerate-highBottleneck — everyone crosses the same day/time window
MuktinathCrowdedReligious pilgrims arrive by jeep year-round
Besisahar-Chame (road section)Low trekker densityMost trekkers now jeep through this section
Upper Pisang-Ghyaru-NgawalLowThe high bypass route is quieter than the road
Tilicho Lake detourLowExtra days deter most trekkers

How to avoid crowds

  1. Trek in late November or early March — shoulder season with decent weather but far fewer trekkers
  2. Take the NATT bypass trails — the high routes are always quieter
  3. Add the Tilicho Lake detour — filters out the majority of trekkers
  4. Start from Besisahar on foot instead of jeeping to Chame — you'll have the lower trail nearly to yourself (though it's on/near the road)

Sources: Mission Himalaya Treks — record-breaking 2024 tourism, Kathmandu Post — solo ban and trekker numbers, Annapurna Encounter — trekking stats.


Summary: Is the Annapurna Circuit Still Worth It?

Yes, with caveats. The road problem is real but solvable with NATT trails. The mandatory guide rule adds cost but provides safety. The altitude is serious — 21 deaths from AMS in the conservation area in a single year — but manageable with proper acclimatization. The 2014 disaster proved that even "safe" trekking seasons carry catastrophic risk.

The Annapurna Circuit in 2026 is not the wilderness trek it was 20 years ago. It is a well-established, tea-house-supported, road-adjacent, guide-mandatory, permit-regulated trek through some of the most dramatic landscape on Earth. If you walk it with realistic expectations — not nostalgia for the 2005 version — it remains one of the greatest multi-day treks in the world.

Walk counterclockwise. Take the NATT bypass trails. Do not skip your Manang rest day. Leave for Thorong La before dawn. And never, ever take a jeep to altitude without acclimatizing first.