The children at Fatima were given a vision of Hell which depicted the damned souls being tossed about in flames.

Hell really is a place where every in is punished in particular, in a just way precisely fitting each sin. It is not solely the horrific loss of the beatific vision, but all those just punishments for every single sin.

For example, if you sin by pleasure of touch, you are visited by particular pains of touch instead, by sense of smell, by stenches, etc. Purgatory has the same sort of justice. On earth a person was supposed to do penance which reflected his sins, i.e. the immodest, by greater modesty, the glutton, by the virtue of fasting, sins of the tongue, hmm I should find one of the horrific visions of punishments for that I read once and post it, but in any case -- but as this penance was not done -- thence Purgatory or Hell.

[This is why I always frown at people who aim for minimums or borderlines of virtue, and complain about higher standards, defending themselves rather than apologizing and admitting the need for progress as a Christian. What are you thinking? Do you think you can get away with living so?]

The ignorant think these punishments are out of proportion with the sins, but in fact, they are actually less than they could be -- people in this life generally simply have no sense of the tremendousness of sin.

Try listening to a traditional Catholic sermon on Hell, there are some moving audios out there.

'If the Devil and his angels, although they are incorporeal, are to be tortured by a corporeal fire, what wonder if souls, even before they are reunited with their bodies, can feel corporeal torments?'

Pope St. Gregory the Great

'This is the way I am dealt with by the priests who are my betrayers . . . Their sentence is condemnation. David condemned those who were disobedient to God, not out of anger or bad will or impatience, but out of divine justice, because he was a righteous prophet and king. I, too, who am greater than David, condemn these priests, not out of anger or bad will but out of justice. Accursed be everything they take from the earth for their own profit, for they do not praise their God and Creator who gave them these things. Accursed be the food and drink that enters their mouths and fattens their bodies to become food for worms and destines their souls for Hell. Accursed be their bodies that will rise again in Hell to be burned without end. Accursed be the years of their useless lives. Accursed be their first hour in Hell that never will end. Accursed be their eyes that saw the light of heaven. Accursed be their ears that heard my words and remained indifferent. Accursed be their sense of taste by which they tasted my gifts. Accursed be their sense of touch by which they handled me. Accursed be their sense of smell by which they smelled delightful things and neglected me, the most delightful of all. May they be accursed by earth and sky and every brute creature. These obey and glorify God, whereas they have shunned him. Therefore, I swear by the truth, I who am the Truth that if they die like this with such a disposition, neither my love nor my virtue will ever encompass them. Instead, they will be forever damned.'

The Lord, to St. Bridget of Sweden

For further reading -- Hell 103 Texts. You will find plenty of fire.

It is the constant teaching of the Church that fire in Hell is real. Unlike the Orthodox who believe that Hell is not so much a physical place but rather a state of soul where there is absence of God (although God still "loves" these reprobate souls).

The Following things can be noted from the Scriptures regarding Hell:

It is a place of torment (Lk 16:28).

It is an abyss (Lk 8:31; Rev 9:1-2,11; 11:7; 17:8; 20:1,3).

It is a fiery furnace (Mt 13:42, 50).

It is a pool of fire (Rev 20:10, 14). It is a fiery pool of burning sulfur (Rev 19:20).

It is a pool of fire and sulfur (Rev 20:10; 21:8), It is a Tartarus (Greek mythological place of punishment 2 Pet 2:4).

Since to dwell in hell is not really a life Scripture speaks of it as a death (Rom 6:21; 8:6; 8:13; 2 Cor 2:14-16).

It is also regarded as a second death (Rev 2:11; 20:6; 21:8) because the first death is the one we live while in sin, because we are dead to God's Grace.

It is regarded as eternal ruin (2 Thess 1:9; 1 Tim 6:9).

It is made know to us that it is a place of eternal fire (Mt 18:8, 25:41;Jude 7, Deut. 32:22, Job 20:26) and that punishment is eternal (Mt 25:46,Isaias 33:14; 66:24; Judith 16:21).

It is a place of destruction (Mt 7:13; Phil 1:28; 2 Pet 3:7), for those condemned there (Mk 16:16; Jn 12:25).

It will be an unquenchable fire (Mk 9:42-47; Lk 3:17), and as fire and sulfur (Rev 14:9-14).

http://www.catholicapologetics.info/apologetics/general/hells.htm

There's also a well supported interpretation that recognizes the hell-fire as symbolic of God's judgment.  It's supported by:

1) The parallel that Jesus makes with "fire and brimstone" which is what is also used to describe the destruction of the Twin Cities, which was a prominent act of God's judgment.

2) The fact that Jesus said Hell is eternal darkness, which wouldn't really make sense if it was full of literal, burning fire.

3) That water throughout the Old and New Testaments is used to represent God's spirit, which is the only thing that can 'quench' the fires of God's judgment.

4) The fact that, at one point, Jesus actually says "The fires of God's judgment", which is an indicator that the Hellfire is representative of God's judgment.

Then again, what I'm asking is if it is a 'dogma' of the Church, not its history of being held and taught by the consensus.

Article 5. Whether the fire of hell will be corporeal?

Objection 1. It would seem that the fire of hell whereby the bodies of the damned will be tormented will not be corporeal. For Damascene says (De Fide Orth. iv): The devil, and "demons, and his men" [Cf. 2 Thessalonians 2:3: "And the man of sin be revealed, the son of perdition."], namely Antichrist, "together with the ungodly and sinners will be cast into everlasting fire, not material fire, such as that which we have, but such as God knoweth." Now everything corporeal is material. Therefore the fire of hell will not be corporeal.

Objection 2. Further, the souls of the damned when severed from their bodies are cast into hell fire. But Augustine says (Gen. ad lit. xii, 32): "In my opinion the place to which the soul is committed after death is spiritual and not corporeal." Therefore, etc.

Objection 3. Further, corporeal fire in the mode of its action does not follow the mode of guilt in the person who is burned at the stake, rather does it follow the mode of humid and dry: for in the same corporeal fire we see both good and wicked suffer. But the fire of hell, in its mode of torture or action, follows the mode of guilt in the person punished; wherefore Gregory says (Dial. iv, 63): "There is indeed but one hell fire, but it does not torture all sinners equally. For each one will suffer as much pain according as his guilt deserves." Therefore this fire will not be corporeal.

On the contrary, He says (Dial. iv, 29): "I doubt not that the fire of hell is corporeal, since it is certain that bodies are tortured there."

Further, it is written (Wisdom 5:21): "The . . . world shall fight . . . against the unwise." But the whole world would not fight against the unwise if they were punished with a spiritual and not a corporeal punishment. Therefore they will be punished with a corporeal fire.

I answer that, There have been many opinions about the fire of hell. For some philosophers, as Avicenna, disbelieving in the resurrection, thought that the soul alone would be punished after death. And as they considered it impossible for the soul, being incorporeal, to be punished with a corporeal fire, they denied that the fire whereby the wicked are punished is corporeal, and pretended that all statements as to souls being punished in future after death by any corporeal means are to be taken metaphorically. For just as the joy and happiness of good souls will not be about any corporeal object, but about something spiritual, namely the attainment of their end, so will the torment of the wicked be merely spiritual, in that they will be grieved at being separated from their end, the desire whereof is in them by nature. Wherefore, just as all descriptions of the soul's delight after death that seem to denote bodily pleasure--for instance, that they are refreshed, that they smile, and so forth--must be taken metaphorically, so also are all such descriptions of the soul's suffering as seem to imply bodily punishment--for instance, that they burn in fire, or suffer from the stench, and so forth. For as spiritual pleasure and pain are unknown to the majority, these things need to be declared under the figure of corporeal pleasures and pains, in order that men may be moved the more to the desire or fear thereof. Since, however, in the punishment of the damned there will be not only pain of loss corresponding to the aversion that was in their sin, but also pain of sense corresponding to the conversion, it follows that it is not enough to hold the above manner of punishment. For this reason Avicenna himself (Met. ix) added another explanation, by saying that the souls of the wicked are punished after death, not by bodies but by images of bodies; just as in a dream it seems to a man that he is suffering various pains on account of such like images being in his imagination. Even Augustine seems to hold this kind of punishment (Gen. ad lit. xii, 32), as is clear from the text. But this would seem an unreasonable statement. For the imagination is a power that makes use of a bodily organ: so that it is impossible for such visions of the imagination to occur in the soul separated from the body, as in the soul of the dreamer. Wherefore Avicenna also that he might avoid this difficulty, said that the soul separated from the body uses as an organ some part of the heavenly body, to which the human body needs to be conformed, in order to be perfected by the rational soul, which is like the movers of the heavenly body--thus following somewhat the opinion of certain philosophers of old, who maintained that souls return to the stars that are their compeers. But this is absolutely absurd according to the Philosopher's teaching, since the soul uses a definite bodily organ, even as art uses definite instruments, so that it cannot pass from one body to another, as Pythagoras is stated (De Anima i, text. 53) to have maintained. As to the statement of Augustine we shall say below how it is to be answered (ad 2). However, whatever we may say of the fire that torments the separated souls, we must admit that the fire which will torment the bodies of the damned after the resurrection is corporeal, since one cannot fittingly apply a punishment to a body unless that punishment itself be bodily. Wherefore Gregory (Dial. iv) proves the fire of hell to be corporeal from the very fact that the wicked will be cast thither after the resurrection. Again Augustine, as quoted in the text of Sentent. iv, D, 44, clearly admits (De Civ. Dei xxi, 10) that the fire by which the bodies are tormented is corporeal. And this is the point at issue for the present. We have said elsewhere (70, 3) how the souls of the damned are punished by this corporeal fire.

Reply to Objection 1. Damascene does not absolutely deny that this fire is material, but that it is material as our fire, since it differs from ours in some of its properties. We may also reply that since that fire does not alter bodies as to their matter, but acts on them for their punishment by a kind of spiritual action, it is for this reason that it is stated not to be material, not as regards its substance, but as to its punitive effect on bodies and, still more, on souls.

Reply to Objection 2. The assertion of Augustine may be taken in this way, that the place whither souls are conveyed after death be described as incorporeal, in so far as the soul is there, not corporeally, i.e. as bodies are in a place, but in some other spiritual way, as angels are in a place. Or we may reply that Augustine is expressing an opinion without deciding the point, as he often does in those books.

Reply to Objection 3. That fire will be the instrument of Divine justice inflicting punishment. Now an instrument acts not only by its own power and in its own way, but also by the power of the principal agent, and as directed thereby. Wherefore although fire is not able, of its own power, to torture certain persons more or less, according to the measure of sin, it is able to do so nevertheless in so far as its action is regulated by the ordering of Divine justice: even so the fire of the furnace is regulated by the forethought of the smith, according as the effect of his art requires.

Article 6. Whether the fire of hell is of the same species as ours?

Objection 1. It would seem that this fire is not of the same species as the corporeal fire which we see. For Augustine says (De Civ. Dei xx, 16): "In my opinion no man knows of what kind is the everlasting fire, unless the Spirit of God has revealed it to anyone." But all or nearly all know the nature of this fire of ours. Therefore that fire is not of the same species as this.

Objection 2. Further, Gregory commenting on Job 10:26, "A fire that is not kindled shall devour him," says (Moral. xv): "Bodily fire needs bodily fuel in order to become fire; neither can it be except by being kindled, nor live unless it be renewed. On the other hand the fire of hell, since it is a bodily fire, and burns in a bodily way the wicked cast therein, is neither kindled by human endeavor, nor kept alive with fuel, but once created endures unquenchably; at one and the same time it needs no kindling, and lacks not heat." Therefore it is not of the same nature as the fire that we see.

Objection 3. Further, the everlasting and the corruptible differ essentially, since they agree not even in genus, according to the Philosopher (Metaph. x). But this fire of ours is corruptible, whereas the other is everlasting: "Depart from Me, you cursed, into everlasting fire" (Matthew 25:41). Therefore they are not of the same nature.

Objection 4. Further, it belongs to the nature of this fire of ours to give light. But the fire of hell gives no light, hence the saying of Job 18:5: "Shall not the light of the wicked be extinguished?" Therefore . . . as above.

On the contrary, According to the Philosopher (Topic. i, 6), "every water is of the same species as every other water." Therefore in like manner every fire is of the same species as every other fire.

Further, it is written (Wisdom 11:17): "By what things a man sinneth by the same also he is tormented." Now men sin by the sensible things of this world. Therefore it is just that they should be punished by those same things.

I answer that, As stated in Meteor. iv, 1 fire has other bodies for its matter, for the reason that of all the elements it has the greatest power of action. Hence fire is found under two conditions: in its own matter, as existing in its own sphere, and in a strange matter, whether of earth, as in burning coal, or of air as in the flame. Under whatever conditions however fire be found, it is always of the same species, so far as the nature of fire is concerned, but there may be a difference of species as to the bodies which are the matter of fire. Wherefore flame and burning coal differ specifically, and likewise burning wood and red-hot iron; nor does it signify, as to this particular point, whether they be kindled by force, as in the case of iron, or by a natural intrinsic principle, as happens with sulphur. Accordingly it is clear that the fire of hell is of the same species as the fire we have, so far as the nature of fire is concerned. But whether that fire subsists in its proper matter, or if it subsists in a strange matter, what that matter may be, we know not. And in this way it may differ specifically from the fire we have, considered materially. It has, however, certain properties differing from our fire, for instance that it needs no kindling, nor is kept alive by fuel. But the differences do not argue a difference of species as regards the nature of the fire.

Reply to Objection 1. Augustine is speaking of that fire with regard to its matter, and not with regard to its nature.

Reply to Objection 2. This fire of ours is kept alive with fuel, and is kindled by man, because it is introduced into a foreign matter by art and force. But that other fire needs no fuel to keep it alive, because either it subsists in its own matter, or is in a foreign matter, not by force but by nature from an intrinsic principle. Wherefore it is kindled not by man but by God, Who fashioned its nature. This is the meaning of the words of Isaias (30:33): "The breath of the Lord is as a torrent of brimstone kindling it."

Reply to Objection 3. Even as the bodies of the damned will be of the same species as now, although now they are corruptible, whereas then they will be incorruptible, both by the ordering of Divine justice, and on account of the cessation of the heavenly movement, so is it with the fire of hell whereby those bodies will be punished.

Reply to Objection 4. To give light does not belong to fire according to any mode of existence, since in its own matter it gives no light; wherefore it does not shine in its own sphere according to the philosophers: and in like manner in certain foreign matters it does not shine, as when it is in an opaque earthly substance such as sulphur. The same happens also when its brightness is obscured by thick smoke. Wherefore that the fire of hell gives no light is not sufficient proof of its being of a different species.