Translation:There was lightning and hailstones.
You do not make it clear what was or was not accepted. Prescriptive English grammar books tell us the correct English is were. However, some people use was here. This can be explained as the there is often treated as the subject and as a singular pronoun. This is a perfectly valid interpretation of the structure, even though it is not the accepted one. The corresponding structures in French (il y avait) and German (es gab) both have singular pronoun subjects.
This means that both was and were should be acceptable. If either was rejected I would suggest you report it next time it happens. D
I wrote There was hail and lightning. I don't know if it accepted hail. It should have done as clachan meallain is the usual translation of hail. Mark says the singular or plural can be used for 'hail' whereas AFB and Dwelly only give the singular. But whatever they say, I am sure the reference here is to 'hail' not 'hailstones' which would not normally be used in a description of weather.
But I suspect the issue was the word order. I would never say lighting and hail. You would always say hail and lighting as English is very strongly biased towards putting the shorter word first. A Google search produced
hail and lightning: 992,000
lightning and hail: 331,000
hailstones and lightning: 36,600
lighting and hailstones: 7,300
I was actually surprised that lightning and hail was as common as it was. However, looking at the hits showed that this was occurring as part of a longer phrase, such as thunder, lightning an hail, probably because thunder and lightning is an accepted phrase, with the hail attached to the end.
This means that, in the absence of a third term, hail and lightning is overwhelming the predominant term, and so should be accepted, as lightning and hail cannot be accepted as normal English. D