Economist John Simpson said the loss of daily output coupled with the cost of repairing damage caused by the weather could amount to around £28m per day.
With a weather warning in force from early yesterday until tomorrow night, the cost could pass £80m.
Snow fell across Northern Ireland for most of yesterday causing traffic carnage and making travelling conditions treacherous, with many workplaces shutting early and sending employees home.
More than 300 schools were closed, shops and restaurants pulled down their shutters early and public transport ground to a halt as the cold snap wreaked havoc.
Given Northern Ireland's already faltering economy, Mr Simpson said the financial cost of the unseasonably late and ferocious winter weather represents a financial loss people here could do without.
"The sheer stoppage of people not being able to do what they want to do because their lives are disrupted equates to a loss of income generated of somewhere in the order of £25m a day," he said.
"Add to that the extra costs of coping with it and you need to add another £3m per day in terms of the damage caused - repairing roads, power supplies etc - and putting things right.
"The weather forecast is that it's going to keep going over the weekend so it could end up costing us more than £80m in three days, or over £110m if it lasts for four days."
Mr Simpson said the unprecedented costs linked to The Beast from the East and Storm Emma as they descend in chaos couldn't come at a worse time for the Northern Ireland which is "not in great shape".
"We really are a much weaker economy now that we would wish - and the weather is not helping," he said.
There was an amber weather alert - meaning possible risk to life and property - for snow across Northern Ireland until 6pm yesterday in counties Armagh, Antrim and Down, with Belfast, Armagh and Newry worst affected.
Numerous businesses sent employees home early - in some cases workers didn't even manage to make to work in the first place - while some rural roads were blocked by deep snow and some remote communities were cut off.
The Met Office has confirmed that yellow weather warnings remain in place for the rest of Northern Ireland until tomorrow.
Snow cancelled all flight operations at Dublin Airport yesterday afternoon, and there were both cancellations and delays at Belfast International Airport and George Best Belfast City Airport.
Shopping centres and high street stores saw shopper numbers fall mid-week due to the Beast from the East after a promising start, according to Diane Wehrle, Insights Director of Springboard.
"The impact on Northern Ireland was felt on Monday with a drop in footfall of -9.3% but on Tuesday footfall rose by +6.5%, the only area of the UK to record an increase," she said.
"As the ferocious weather moves westwards over the next few days and Storm Emma enters the fray, however, we anticipate that footfall in Northern Ireland will worsen substantially."
Retail NI chief executive Glyn Roberts said the majority of small independent shops had opened in Northern Ireland yesterday, although many were operating a skeleton staff.
"There is no doubt this storm has cost the Northern Ireland economy severely, with thousands of businesses closing and extensive damage to property," he said. "But it is a mixed bag. People tend to shop at local shops rather than venture into town to the supermarkets in this weather, so some of our members are doing okay."
Several court sittings were affected yesterday, with more disruption expected today.
Sporting fixtures are also hit, with tonight's Ulster rugby match already called off. The weekend's GAA programme has also been wiped out.