"fierce increase" is correct and can be used in written English
You can use it to describe an increase that is sudden and extreme. For example, "The price of gas has seen a fierce increase this week."
In the US the federally determined minimum wage is US$7.25 (less than A$10 an hour) although a fierce fight to increase it to $15 has led to an increase in some states.
So desperate was the Pataki administration to ensure adequate supply that it ordered 10 small generators installed around the city in 2001, over fierce opposition, to increase the available power.
This makes her roundly unpopular with black and white alike, but inspires in Genna a fierce loyalty that increases as the harassment of Minette begins and then escalates.
That has a very different look and feel than a company that is run with concentrated authority, promoting fierce competition and increasing profits by any means necessary.
The violent response to these protests by Ferguson's law enforcement set off a fierce debate about the increasing militarization of the American police force.
The plan has ignited a fierce debate about potential increases in population, traffic, demands on sparse water supplies and air pollution in close proximity to a World Heritage Site prized for panoramic views of multihued canyons shaped by the erosive forces of water and wind.
The Bloomberg administration on Monday issued new warnings about New York City's vulnerability to climate change, offering updated data to encourage businesses, residents and perhaps even future mayors to better prepare against hotter weather, fiercer storms and increased rainfall.
The Philippines is facing an increasing number of fierce typhoons, said Alicia Ilaga, a member of that country's delegation.
Those projections increased an already fierce competition among Mr. Obama, Mrs. Clinton and John Edwards, all of whom will share a stage Monday at a debate that will be focused, in part, on racial issues.
But, now that several crises have emerged upon his watch, there will be questions about why little was done to prevent them in the first place.These questions are likely to be especially fierce, because each bail-out increases the odds that another one will be necessary.
