You will have to have more than the basics to survive unexpected mountain weather, which you should always plan for. What you need to bring depends on the length of your climb, how remote the location is and what the weather forecast is saying. This list is for multi-day trips you will have to add to the list depending on how many days you are gone for and can pare down the list for day trips. This list is comprehensive, but it is not the final word on things.
Climbing Gear
(Hardware quantities depend on route)
-climbing pack
-crampons
-harness
-ice axe
-locking carabiners
-non-locking carabiners
-prusik cords
-runners – singles and doubles
-snow protection gear
-rope(s) (dry preferred)
-harness
-helmet
-belay/rappel device
-pulley
-hand protections (tape, gloves)
-headlamp + extra batteries
For technical or mixed routes
-nuts
-nut tool
-hexes
-ice tools
-ice screws
-camming devices
Crevasse Rescue Gear
-Snow picket
-slings (double and single)
-pulleys
-20ft of 5-7 mm cordelette
Navigation
-map (waterproof map preferred)
-guidebook / route description
-compass
-altimeter watch
-GPS
-cellphone
-personal locator beacon or satellite messenger
-battery pack or solar panel to charge devices
Clothing and Footwear
-long underwear
-underwear and sports bra (if needed)
-quick drying t-shirt
-mountaineering pants
-1 pair soft shell
-1 pair hard shell
-hard shell jacket
-soft shell jacket
-lightweight fleece
-lightweight synthetic puffy jacket with hood
-larger parka (for late-season trips)
-fleece pants
-long sleeve shirt (for sun and bugs)
-boots (must be crampon-compatible)
-socks plus spares
-insulated booties for camp/hut wear
-gloves or mitts
-warm hat
-sun hat
-bandana or buff
-neck gaiter or balaclava
-gaiters
Overnight Gear
-Mountaineering tent
-sleeping bag (rated appropriately)
-sleeping pad
Food, Eating and Hydration
-stove
-fuel
-cookset
-dish/bowl
-eating utensil(s)
-insulated mug/cup
-biodegradable soap
-small quick dry towel
-water reservoir
-Nalgene water bottle
-water filter or purifier
-meals and snacks plus an extra day’s supply of food
-trash bag
Emergency and First Aid and Tools and Repair Items
-First aid kit
-whistle
-signaling mirror
-lighter/matches (in watertight container)
-Fire starter
-Emergency shelter
-knife or multi-tool
-gear repair kit
-duct tape strips
Health and Hygiene
-hand sanitizer/wipes
-toothbrush and toothpaste
-trowel
-toilet paper and sealable bag (to pack it out)
-menstrual products
-prescription medications and other meds
-prescription glasses
-sunglasses
-sunscreen
-SPF lip balm
-nose guard
-insect repellent
-Urinary products (optional)
-additional blister treatment supplies (optional)
Personal Extras
-Small notebook with pen/pencil
-trekking poles
-reading material
-cards or games
-compact binoculars
-insulated sit pad
-handwarmer packets
-permits
-credit card and/or cash
-ID
-Car keys