Officers were called at 7.18am today (1st March 2018) to reports of a collision involving a lorry and a van, on the southbound carriageway, just two miles prior to the Tot Hill Services.
The driver of the van, a 46-year-old man, from Southampton, was pronounced dead at the scene.
His next of kin have been informed and are being supported by specialist officers.
His front seat passenger was taken to the John Radcliffe Hospital, Oxford. His condition is described as life-changing.
The lorry driver was uninjured.
A short time later, at 7.52am, we got reports of a second collision on the A34 northbound at Highclere.
This involved two lorries and a car.
The male driver of one lorry was taken to the John Radcliffe Hospital with serious life-changing injuries.
The road closures will be in place until this evening to ensure the road is completely safe before it is reopened.
Sgt Barry Long, from the Joint Roads Policing Unit, said: “We would like to thank everyone for their patience while we deal with this incident, in what are particularly difficult conditions, with temperatures as low as minus 7C.
“Our thoughts are with the loved ones of the deceased as this time.
He added: “We have been working hard with our colleagues in the emergency services and highways to ensure those stuck in traffic get away safely and that the road is reopened as quickly as possible.
“All those who were caught up in the incident have now been able to drive away from the scene.
“However, due to extensive damage to the barriers and their location, our colleagues from Highways England have informed us that the road is expected to be closed until this evening.
“We know that this will cause disruption to many people, so if you can avoid the area please do.
“We will keep you updated regarding the road closure, so please keep checking social media for the latest information.”