The phrase "a dramatic indication" is correct and usable in written English.
It can be used to describe a strong or significant sign or signal of something, often in a context where emotions or events are heightened.
Example: "The sudden drop in temperature was a dramatic indication of the approaching storm."
Alternatives: "a striking sign" or "a powerful signal."
This was a dramatic indication to the colonists of the drawbacks of the Spanish monopoly, especially when that monopoly was exercised by what was, in European terms, an underdeveloped country.
Gold, the traditional safe haven in times of market turmoil, has soared in value overnight, jumping 22% in sterling terms in a dramatic indication of worldwide panic over Britain's exit from the EU.
Avatars of a gang-related West Coast-East Coast feud, Tupac Shakur and Christopher Biggie Smalls Wallacece died the deaths of their alter egos — a dramatic indication that in music, as distinct from movies and television, the separation sometimes disappears between art and artist.
The federal indictments in December of 18 former and current sheriff's deputies are the latest and most dramatic indication of a department in desperate need of change.
When we met Eleven, she was neutered by a buzz cut; now her hair has flowered into a full and sloppy bob, like a dramatic first indication of womanhood.
In 1998, CEO Roger Enrico made the system mandatory a dramatic indication of its value given Pepsi's decentralized culture and the home office's general reluctance to impose companywide rules.
It is probably the most dramatic indication of recent years of the change in attitudes to railways.
In the main cabin, however, as the planeload of passengers settled down sleepily, the cabin crew suddenly had their first dramatic indication that something was wrong.
Perhaps the most dramatic indication of the moderates' weakness is that in the last six months the hierarchy of the Sikh religion been taken over by extremists who condone or engage in violence on behalf of their cause.
An even more dramatic indication is the sparkline showing the number of users increasing (apparently) significantly over the year.
The excellent outcome in stability and function, the simplicity of the technique (increase in operative time does not exceed 15 min), the minimal cosmetic impact resulting from the percutaneous technique, and the low failure rate has led to a dramatic expansion of surgical indications at the study centre during the last five years.
