As Mike has pointed out there are a number of good reasons for thinking twice about standing out in the open when a storm is close by, as is often the case a number of these reasons aren't particularly obvious when charged up on chase adrenalin.
My reasoning for not standing out in the open when during storms probably comes from having been out in the open during storms too many times whilst not being charged up on chase adrenalin...
The logic behind my reasoning can be explained by thinking of some simple stats
Lets say the overall chance of being physically struck by lightning in Australia each year is 1 in a million
If you are not near a storm i.e. further than 15km from a storm, or you are in a building, taking appropriate shelter in an enclosed metal cage (car) chance of being physically struck - nil
If you are outdoors near but still at a distance say >5km from a storm, chance of being struck - extremely unlikely.
If you are outdoors under the anvil / just starting to get the first drops or rain from a highly charged electrical storm - most people would recognise "you are in danger" - even if it is still say a 1 in a thousand chance of being directly hit.
On that basis - stand out in the open under the anvil of an electrical storm a thousand times, chance of being directly hit- 1 in 1, almost certain..
Logic:- the more you undertake a risk the more likely it is the outcome will occur..
Remember the total number of people who get hit by lightning is a lot higher than the number killed (the ones you tend to here about) "Australia has app 5-10 deaths and 45 serious injuries per year as a result of lightning strikes" -
http://www.lrc.com.au/doc/LightningSafetyRecommendations.pdf (although data from the 1990's showed a decrease to only 23 fatalities with a mortality rate of 10% of lightning strike recipients, for that 10 year period -
http://www.mja.com.au/public/issues/177_01_010702/mak10009_fm.html )
The following is a few more ideas and reasoning that you can do some more research on before you let the chase adrenalin out way your rational thinking on your next chase.
If you are out in the open during a storm being in the vicinity of (but not near / right next to or under in the case of trees) tall objects, preferably metal, can (but see below for potential difference from close strikes) offer a radius "cone" of "increased" protection depending on height of up to app 30m from the object, whilst that "cone of protection" is not failsafe - lightning may still hit you rather than the tall object, it apparently does decrease the chances of being hit. I guess one analogy would be how many people get struck in cities where there is a likely greater number of people outdoors but a lot more tall objects. As opposed to say golfers out on an open golfing green.
If you have no other option but to remain in the open, reduce your height, squat low with your feet together. (Do not lie down)
Why feet together.. if lightning does strike nearby lets say within 10m and you are out in the open on a grass surface for arguments sake, if you are standing side on to the strike, you will have a large potential difference in voltage between one leg and the next. If you are standing feet apart, facing the strike or the strike is directly behind you the potential difference between your legs is small or negligible. Likely result.. person standing legs apart side on to the strike dies, person legs apart facing the strike lives.
You do not have to take a direct hit to be killed by lightning. If a person was for instance standing feet wide apart, on wet grass, with bare feet, that would mean a lot less resistance = easier and bigger flow of electricity, danger distance from the strike increases significantly, in this case it may be up to 100m. Hanging on to or being in contact with other objects esp. metal ones i.e. leaning up against a car, or being in contact with a fence just increases the likelihood of a big potential difference between you and the possible strike. (
http://www.telegraph.co.uk/news/worldnews/southamerica/uruguay/3249895/Fifty-two-cows-are-killed-after-lightning-hits-a-wire-fence.html)
To give an instance of electric shock away from the actual strike, a mate of mine Mick was standing (bare feet)under a carport app 1m closer to the edge of the concrete, app 4-5m back under the carport roof during a wild storm, the rain had blow in under so he was standing on wet concrete I was standing on dry concrete. A lightning bolt struck over 100m away Whilst Mick wasn't standing feet wide apart or side on he still received a mild electric shock whilst I didn't.
If you have a vehicle in most chase cases you will have, you should be safe inside the vehicle as long as you don't touch the frame or any metal objects linked to the frame.
If your car is hit by lightning keep away from it's tires, don't change any blown tires immediately they can re-explode (unless completely shredded) from a detonation of explosive gasses (not pressure build up). Take it easy don't drive like Mark Webber after taking a lightning hit, as your chances of tires blowing out in the period up to 24hrs after the hit has just increased dramatically. Tires are most likely to blow out directly after or in the few minutes following a hit but may take up to 24hrs to blow.
Bit of extra food for thought and reasons to do your photography from inside your vehicle...
Cheers
PD