In winter, with regards to hillwalking, a fairly sensible adage is to take enough kit to cover any eventuality; many warm layers, extra food, crampons, ice axe. This ethos can be taken to extremes though, with folk being chided for not fully kitting-up for fairly benign walks. Many keyboard warriors would have folk burdened under rucksacks worthy of an Everest expedition, even for what are straightforward and relatively low-risk strolls.
The winter mountain runner however, has to balance weight against mobility; we can’t take the kitchen sink. There is always going to be an element of risk in not covering any eventuality, but that’s OK as long as it is considered, and managed.
Before even setting off, choosing a route that is safe for the prevailing and likely conditions on the ground, that is manageable within the daylight available, and with a safety margin built in, is key.
To do this, one needs as much current information as one can gather, and there are a few ways to bolster this beyond mountain weather forecasts, which only tell you what it is happening and coming up air-side (temperature, wind, precipitation) and not what is the current state of the earth-side (snow depth, ice), either of which can hinder speed of travel.
In my primary area of mountain terrain (Scotland’s Cairngorms) there’s a handy website that has daily reports over the winter: The Scottish Avalanche Information Service (SAIS). These provide a valuable insight into cover and condition, with an evaluation of avalanche risk and some photos.
Every day, other people are putting boots on the ground so to speak, and in the modern era they often leave an immediate ‘trail’ online: photographic evidence on social media.
For my planned destination. e.g. for Lochnagar, on instagram I can search for hashtag #lochnagar and also by location Lochnagar. These searches have two sections: top posts and recent, with recent being the useful one. Each post will have a date, and the text may indicate whether the photo was taken recently or is just a new post of an older photo. For popular locations, there will normally be a few photos every few days, however not so much for less popular ones which may not have anything recent enough to be useful. Towns near to mountains will often have photos with the mountains in the background, or locals commenting on driving/walking conditions.
The same type of searching can be carried out on twitter and facebook, with facebook in particular having many groups and pages dedicated to the general area of topic, even some specific to ground conditions in winter. Ground conditions in UK mountain areas Ground conditions in Scottish mountains. Some of the social media accounts of mountain rescue teams have useful updates. There are also some webcams available that will show scenes in relevant areas e.g. http://www.snowgatecameras.co.uk/
This modern concept of ‘web-scouting’ of course has quibblers and agitates the old-fashioned into a blustering of whataboutery: “conditions can change rapidly, you should be prepared for all conditions, you can’t trust reports on the internet”. These are all true to a certain extent but miss the salient point: more information is better than no information. Ground conditions may change rapidly, but generally progress over days, and recent historical data is useful in planning.
* More information is better than no information *
Some example URLs I use for checking some of my common destinations:https://www.instagram.com/explore/locations/273486454/lochnagar/ https://www.instagram.com/explore/tags/lochnagar/ https://www.instagram.com/explore/locations/261853523/cairngorms/ https://www.instagram.com/explore/tags/cairngorms/ https://www.instagram.com/explore/locations/233548701/ballater-aberdeenshire/ https://www.instagram.com/explore/tags/ballater/ https://www.instagram.com/explore/tags/benmacdui/ https://www.instagram.com/explore/locations/259044391/ben-macdui/ https://www.instagram.com/explore/locations/255826341/braemar/ https://www.instagram.com/explore/tags/braemar/ https://www.instagram.com/explore/tags/mountkeen/ https://www.instagram.com/explore/locations/253930735/mount-keen/ https://www.cairngormmountain.co.uk/weather-webcams/mountain-report/