It's a funny surface, woodchip with some bark mixture, so I will tell you a few things about it while I try to take my mind off a serious matter I have no control over but will keep everything crossed for it no longer being serious.
First of all, let me tell you, I am fully qualified to pass all the below things on...I've spent over 1.5 year teaching on woodchip surface, seen it in sunshine, rain (just a normal English rain), pouring rain, a drizzle, fog, frost and snow. I have seen quite a lot of it too, sometimes too much (when it was topped up without the need for it) and not enough of it (when the top up needed wasn't done).
1) Woodchip surface is a rubbish one really to have outdoors.
2) The best combination of weather for woodchip is as follows (unfortunately the stages themselves are not great to work through):
a) a few days of decent frost with below zero temperatures. This freezes the surface and gives it a very slippery ice rink like quality. Almost unrideable unless you are fine with constant slipping.
b) a day or so of mild weather which allows the surface to soften: while this happen parts will still be very slippery, other parts will have plenty of grip so it's a bit like driving on a road with ice showing up from time to time, usually when you are gathering speed and least expect it...
c) third day after the freeze: surface is good, have a nice softness to it over the top, pleasant firmness over deeper layers, good grip and rides well.
3) Woodchip surface isn't good for your footwear...your boots will work like magnet for all the tiny pieces of dirt and pieces of wood.
4) You will find it wedged into every single crack in the leather, it will stuck to the soles of your boots and wriggle it's way under the straps of your gaiters/half-chaps.
5) Your overtrousers will be covered all the way up to your knees in a fascinating mixture of soil, wood and shavings like pulp if you happen to teach in the rain.
6) If the stable owner has just dropped a new layer on you will smell of woodchip for good few hours after your day on the surface.
7) Ponies love EATING this surface which means you WILL loose your clients while the ponies stop suddenly, drop their heads and peruse the woodchip with passion.
8) Horses also like EATING this surface. They will drop their necks and endulge in finding edible pieces of god knows what giving your beginners a mild heart attack.
9) If you are lucky and the weather is gorgeous for longer than a week the woodchip surface dries so much that walking on it feels like venturing onto Sahara desert - in other words, it's bloody tiring to walk on it not to mention run on it should you need to catch a runaway pony.
10) If you are unlucky enough to work in a driving rain week in and week out the woodchip surface will not help you much. Think walking through swamps and you will get the idea.
11) If the rain persists you may find that you can run xc clinics without even leaving the arena. There will be a fantastic water jump down your centre line.
12) If the people who top up the surface think it's ok to just dump random amounts of wood chip at every letter around the arena you may even be able to include a how-to-tackle-a-bank jump sessions.
13) You may find it difficult to practice dressage tests as the horses get so happy running in the ditch (the outside track) that they rarely want to explore the rest of the arena (where the hills are)
14) Your best bet is to just sit on the fence and let the riders and horses deal with the surface.