During very windy conditions I find this advice helps to steady things down.

Keep an eye on the weather forecast, it's better to be prepared rather than having to rush around.

It may seem obvious but, most awnings are not fastened down correctly. Make sure all your ground pegs are secure. If they are loose re-site the peg and hammer home.
Use storm straps, you should always carry a couple with you, put them right over the awning or over the towing frame if you can fix to the ground.
Secure outside equipment, tables and chairs can be folded or even tied together and put underneath the van.
Think about packing away the awning and store underneath the van.
If possible, park your car on the side of your van that is likely to recieve the brunt of the wind, park it as close to your as you are able to your van. This will be a great help in deflecting the wind.
Close all your windows and "pop top". This will enable you be as aerodynamic as possible and will assist the wind in sliding over the top or around the corners.

Be pleased that you have an Eriba caravan as they are very well designed with rounded corners and top which is excellent at deflecting the wind.
Sit tight, your added weight in the van make it more stable.

Be glad you are not in a big white square box, now get the kettle on.

As discussed in the other thread running, about high winds.
Definitely worth battening down the hatches.
We spent 2 week's on the French coast in our old WWB.
It was horrific, most nights you could feel the whole van moving about. Our little Erica was rock solid last night.