The 24-year-old West Aucklander was walking up the glacier, and was on a rock outcrop at 5200m, about 30 minutes' walk from the base camp, when the first earthquake struck about noon Nepal time.
That was soon followed by the avalanche, which killed at least 18 people.
"We all thought we slipped at the same time, then the ground began to boil," Ms Farrington said in an email to her parents, who are relieved to learn that she escaped injury.
"Crouched against the ground, we saw the cloud of snow screaming down ... Tek, our guide, screamed at us to run. Walking uphill at that altitude is the hardest thing I've ever done. Sprinting was going to kill me if the avalanche didn't.
"My heart felt like it was going to explode and my legs were lead. Knowing there were only a couple more steps in me, I dropped by a rock big enough to hold and pulled my knees under my chest.
"The snow hit and it was deafening. But we had got far enough and there was only about 8cm.
"I threatened to punch anyone who wanted to go on and ... everyone agreed to turn back to Gorak Shep [a hamlet about 4km down the valley from the Base Camp].
"Five minutes later and we felt the next tremor and we were running through a gully. All I was thinking was, 'Not now. I survived the first, don't take me on the second.'
"We [trudged] down through the valley and with GS [the village] in sight, the call to run came the third time. My body had nothing left. Then I felt a hand on my pack pushing me forward. This turned into the most needed hug of my life when we got the all-clear.
"We were the first group in but others slowly trickled in after. Then came the [6.7 aftershock] and we all ran back outside ...
"Stumbling up to bed and still being awake for the three aftershocks didn't bode well for the massive day coming up.
"We [trudged] down and reached Pheriche, which was flat. And village after village was the same. Last night we stayed ... [at] Tengboche. Half the building was filled with cracks and holes. We were sharing with another Kiwi team - Peter Hillary at the helm."
Ms Farrington said she was now in Namche at 3500m again.
"Here it is safe and our guides are trying to figure out the next step.
"I've never been more scared in my life. Every loud noise is making us run for cover."
Ms Farrington's father, Chris, said the family had been anxious about Elizabeth.
"She rang us within quarter of an hour of the earthquake. I don't know how she managed to do that. She sounded very frightened and upset. You could just tell from her voice.
"Just the fact we have heard from her meant we haven't had two days of worry."
Survivors' grim stories emerge as climbers try to nab chopper flights off Everest
Earthquake-shaken Mt Everest climbers and trekkers are scrambling to arrange helicopter flights off the mountain and out of the region following Saturday's killer avalanche at the Base Camp.
All 30-plus members of Kiwi company Adventure Consultants' expedition who were at Camp 1 and Camp 2, which are above the dangerous Khumbu Icefall, have been flown by helicopter to the Base Camp, but there are fears for other teams stranded part-way up the world's highest mountain.
British climber James Grieve, 52, told the Sun newspaper by satellite phone from Camp 1 that the rescue effort was being hampered by storms and his party's supplies would last just days.
It is assumed that the route through the icefall, re-established and maintained by Sherpas each season, has been damaged by the quakes causing ice towers to collapse.
Outside magazine reported that because of the reduced capacity of helicopters at altitude, around 40 flights would be needed to evacuate the 100 to 120 mountaineers above the icefall at the time of the first quake.
An Argentine guide, Damian Benegas, had led a team down a short way from Camp 1 to scout the icefall route but returned back uphill in the face of continuing aftershocks.
Survivors' stories are emerging, including that of a cook who clawed his way out of the snow after the massive airborne avalanche blasted through the tents at the Base Camp.
A video of the avalanche posted on the internet by Jost Kobusch shows climbers' curiosity turn to terror as the avalanche cloud - at least 50m high and consisting of snow, small ice chunks and possibly rocks - engulfs them, and then is gone in an instant, leaving just centimetres of snow on the ground.
In the video someone asks if they should take shelter in their kitchen tent, only to hear the answer, "The kitchen tent is gone."
The avalanche killed at least 18 people - including five of Adventure Consultants' Nepalese staff - and injured more than 60 of the nearly 1000 people at the Base Camp.
Aftershocks continue to rock the Himalayan nation.
There are reports of more avalanches on the slopes above the Base Camp, and that the Everest Base Camp walking track has been cut by landslides.
A Base Camp cook, Bhim Bahadur Khatri, 35, told the Associated Press in Kathmandu, where he had been evacuated to by air with other injured Sherpas: "I was cooking for my team in the meal tent when the earthquake hit. We all rushed out to the open and the next moment a huge wall of snow just piled on me.
"I managed to dig out of what could easily have been my grave. I wiggled and used my hands as claws to dig as much as I could. I was suffocating. I could not breathe. But I knew I had to survive. I dug a few more feet until I was out of the snow and could breathe. I looked around and saw the tents all torn, crushed and many people injured. I had lived, but lost many of my friends."
Steve Moffat, the NZ operations manager of Adventure Consultants, said from the company's Wanaka base that eight of its crew were evacuated by air from the Base Camp with injuries such as head trauma and limb fractures. Clients who had been at the higher camps were "all relieved to be down at Base Camp" and had been in touch with their families by satellite phone. The company is trying to arrange helicopter transport for its team because of reports of damage to the foot track down from the Base Camp to the region's main airstrip.
Peter Hillary's trekking group of King's College old boys from his year-group at the South Auckland school had made it to a lodge in Tengboche village, more than 20km down the valley from the Base Camp, said the wife of one group member. They had spent their first night after the earthquake at Gorak Shep, about 4km from the Base Camp. She spoke briefly to her husband yesterday and said he was in good spirits.
